Do OT scriptures clearly indicate sacrifices will be replaced?

Yes, the OT clearly says that animal sacrifices would cease with one final everlasting never to be repeated or represented sacrifice.

Psa. 40:6 (Septuagint) Sacrifice and offering thou wouldest not; but a body hast thou prepared me: whole-burnt-offering and [sacrifice] for sin thou didst not require.

David is saying God does not desire sacrifices and offerings. See also Ps. 51:16, 1 Sam. 15:22, Isa. 1:11, Hos. 6:6.

YET, in the same breath, David prophesies that God nevertheless prepared a body. Why? If God does not want sacrifice, why prepare another body? It is God's will.

Psa. 40:7-8 (Septuagint) Then I said, Behold, I come: in the volume of the book it is written concerning me, I delight to do thy will, O my God: yea, thy law is within my heart.

Who is the I? Not David because the sacrificial system continued, but rather Messiah.

With that, we know the sacrificial repetitions would end.

The Prophecy of God to Malachi

^{Jesus Institutes the Eucharist}

As early as 70 A.D. the prophecy of Malachi concerning a daily sacrifice (the Eucharist) offered among the Gentiles was seen by Christians to be a definitive abolishment of the Jewish sacrifical system:

"Assemble on the Lord’s day, and break bread and offer the Eucharist; but first make confession of your faults, so that your sacrifice may be a pure one. Anyone who has a difference with his fellow is not to take part with you until he has been reconciled, so as to avoid any profanation of your sacrifice [Mt. 5:23–24]. For this is the offering of which the Lord has said, ‘Everywhere and always bring me a sacrifice that is undefiled, for I am a great king, says the Lord, and my name is the wonder of nations’ [Mal 1:11, 14]"

—Didache 14 [A.D. 70].

"Make certain, therefore, that you all observe one common Eucharist; for there is but one Body of our Lord Jesus Christ, and but one cup of union with his Blood, and one single altar of sacrifice—even as there is also but one bishop, with his clergy and my own fellow servitors, the deacons. This will ensure that all your doings are in full accord with the will of God."

—Ignatius, Epistle to the Philadelphians 4 [A.D. 110]

"God speaks by the mouth of Malachi, one of the twelve [minor prophets], as I said before, about the sacrifices at that time presented by you: ‘I have no pleasure in you, says the Lord, and I will not accept your sacrifices at your hands; for from the rising of the sun to the going down of the same, my name has been glorified among the Gentiles, and in every place incense is offered to my name, and a pure offering, for my name is great among the Gentiles . . . [Mal. 1:10–11]. He then speaks of those Gentiles, namely us [Christians] who in every place offer sacrifices to him, that is, the bread of the Eucharist and also the cup of the Eucharist."

Justin Martyr, Dialogue with Trypho the Jew 41 [A.D. 155] [emphasis mine]

"He took from among creation that which is bread, and gave thanks, saying, ‘This is my body.’ The cup likewise, which is from among the creation to which we belong, he confessed to be his blood. He taught the new sacrifice of the new covenant, of which Malachi, one of the twelve [minor] prophets, had signified beforehand: ‘You do not do my will, says the Lord Almighty, and I will not accept a sacrifice at your hands. For from the rising of the sun to its setting my name is glorified among the Gentiles, and in every place incense is offered to my name, and a pure sacrifice; for great is my name among the Gentiles, says the Lord Almighty’ [Mal. 1:10–11]. By these words he makes it plain that the former people will cease to make offerings to God; but that in every place sacrifice will be offered to him, and indeed, a pure one, for his name is glorified among the Gentiles."

Ireneus, Against Heresies 4:17:5 [A.D. 189] [emphasis mine]

And so on.

Protestant early Church historian, J.N.D. Kelly says the following:

"It was natural for early Christians to think of the Eucharist as a sacrifice. The fulfillment of prophecy demanded a solemn Christian offering, and the rite itself was wrapped in the sacrificial atmosphere with which our Lord invested the Last Supper. The words of institution, ‘Do this’ (touto poieite), must have been charged with sacrificial overtones for second-century ears; Justin at any rate understood them to mean, ‘Offer this.’ . . . The bread and wine, moreover, are offered ‘for a memorial (eis anamnasin) of the passion,’ a phrase which in view of his identification of them with the Lord’s body and blood implies much more than an act of purely spiritual recollection" (J. N. D. Kelly, Early Christian Doctrines, 196–7).

As for me, I see this prophecy as related:

Isaiah 66:18-21

But I know their works,¹ and their thoughts: I come that I may gather them together with all nations and tongues: and they shall come and shall see my glory. 19 And I will set a sign among them, and I will send of them that shall be saved, to the Gentiles into the sea,² into Africa, and Lydia them that draw the bow: into Italy, and Greece, to the islands afar off, to them that have not heard of me, and have not seen my glory.³ And they shall declare my glory to the Gentiles: 20 And they shall bring all your brethren out of all nations for a gift to the Lord, upon horses, and in chariots, and in litters, and on mules, and in coaches, to my holy mountain Jerusalem, saith the Lord, as if the children of Israel should bring an offering in a clean vessel into the house of the Lord. 21 And I will take of them to be priests, and Levites, saith the Lord.

^{1 Rev 2:2}

^{2 1 Cor 1:18}

^{3 Rom 9:25}

I don't know of any OT scriptures which say outright that sacrifices will be replaced, but there are OT scriptures which allude to a Messiah which will bring about permanent redemption from sin.

At Psalm 37:29, there is a prophecy about righteous ones having eternal life.

²⁹ The righteous will possess the earth,
And they will live forever on it.

And yet, at Psalm 49:6-11, it's revealed that no human could ever offer a ransom sacrifice which brings eternal life.

⁶ Those who are trusting in their wealth
And who boast about their great riches,
⁷ None of them can ever redeem a brother
Or give to God a ransom for him,
⁸ (The ransom price for their life is so precious
That it is always beyond their reach);
⁹ That he should live forever and not see the pit.

Psalm 72 describes a "king" which will bring about peaceful conditions to the Earth by which "people obtain a blessing".

¹⁷ May his name endure forever,
And may it prosper as long as the sun.
May people obtain a blessing for themselves by means of him;
May all nations pronounce him happy.

Finally, in Isaiah 53:10-12, it's revealed that the Messiah will "present his life as a guilt offering" so that he can "bring a righteous standing to many people."

¹⁰ But it was Jehovah’s will to crush him, and he let him become sick.
If you will present his life as a guilt offering,
He will see his offspring, he will prolong his days,
And through him the delight of Jehovah will have success.
¹¹ Because of his anguish, he will see and be satisfied.
By means of his knowledge the righteous one, my servant,
Will bring a righteous standing to many people,
And their errors he will bear.
¹² For that reason I will assign him a portion among the many,
And he will apportion the spoil with the mighty,
Because he poured out his life even to death
And was counted among the transgressors;
He carried the sin of many people,
And he interceded for the transgressors.

From this, we can draw the conclusion that, by means of the Messiah, repeated sacrifices will no longer be required in order to have a good standing with God. Instead, God would then establish a "new covenant" under which God says, "I will forgive their error, and I will no longer remember their sin." —Jeremiah 31:31-34

The writer to the Hebrews [Heb 1:1,2] makes it clear that the very repetition of the sacrifices, themselves, is proof of the fact that they are not effectual. And the only reason for their repetition could only be an intelligent expectation that something better would arise.

For the law […] can never with those sacrifices which they offered […] make the comers thereto perfect. For then would they not have ceased to be offered ? [KJV]

[…] because that the worshippers, once purged, should have had no more conscience of sins.

But in those [is] a remembrance again of sins every year.

As with any repetitive ritual, some will be content, thoughtlessly, to continue with a habit thinking that a mere performance will be effective spiritually. And it is clear that many of old were so contented with the outward representation - and looked no further.

But to the intelligent worshipper it was evident, in the very repetition, that this was but a means to an end, but an herald of a reality yet to be revealed.

Until that revelation, there could only be the representation. The prophets speak in many places, in many ways, of that which was promised. But I can only think of one definite prophecy that is relevant to this particular question, which is Daniel 9:27 :

[…] shall cause the sacrifice and oblation to cease,

but it is a mysterious prophecy and I would not wish to venture to say more about it.