Who are the "little ones" in Luke 17:2?

Yes , little ones means those newly converted , or young in the faith , you can't make a child sin they aren't old enough to know right from wrong. This is in regard to Lk 17.

Who are the little ones In Luke 17:1-3. If one is to rightly handle or divide God's Word (https://www.biblegateway.com/passage/?search=2%20Timothy%202%3A15&version=ESV;KJV), then first we must consider the context, or what the verses surrounding it say, but also it is useful to look at how a concept or word is presented through out the Bible. John MacArthur does an excellent job of this. In his sermon covering these verses of Luke in paragraph 18 he answers your question in detail:

"Who are these little ones? Well Matthew 18 is a parallel instruction from Jesus in more detail than this. And there He says, "These little ones who believe in Me." Believers. Not talking about children, not talking about infants, He's talking about believers. And they were all spiritually young. Now remember, Jesus has just been teaching the gospel of the Kingdom for the first time through His ministry. For some of these people they're just now hearing it and understanding it and embracing it and believing it and they are spiritual children, they are little ones in terms of their spiritual development. He's very protective of His little ones. In fact in Matthew 18 He says, "Do not belittle any of My children, My little ones for whom the angels of heaven have such concern that they watch My face all the time in order that they can pick up My concern and be dispatched to the aid of these little ones." In Matthew chapter 18, in fact, you have an even broader statement of this same issue, well worthy reading. Listen to what our Lord said on that occasion. Verse 6, Matthew 18, "Whoever causes one of these little ones who believe in Me to stumble, it is better...that means it is to his advantage...for him that a heavy millstone be hung around his neck and that he be drowned in the depth of the sea. Woe to the world because of its stumbling blocks for it is inevitable that stumbling blocks come, but woe to that man through whom the stumbling block comes." And then in verse 10 He says, "See that you do not despise or belittle or show disdain for one of these little ones." They are so precious to Him that it's like a shepherd. If a man has a hundred sheep and one of them goes astray, doesn't he leave the ninety-nine on the mountain and go and search for the one that is straying? It turns out that when he finds it, I say to you, he rejoices over it more than the ninety-nine which have not gone astray, thus it is not the will of your Father who is in heaven that one of these little ones be devastated. How you treat other believers is a very important thing to God."(Found here: https://www.gty.org/resources/sermons/42-217/four-hallmarks-of-humility-part-1?term=Luke%2017:1-3)

The simple answer is new believers. As you can see, God's Word can and should be interpreted by looking within the scriptures for answers.

All of the commentaries on this passage from the Church Fathers back to Clement (d. 99 AD) indicate that "little ones" refers to believers and not specifically to children. This includes Clement's first epistle to the Corinthians (XLVI), Athanasius History of the the Councils (I.2), and Cyril of Alexandria's overall commentary on the Gospel of Luke.

The offenses referred to in these writings are heresies. Cyril writes:

What are the offences which Christ mentions as being in every way certain to happen? Offences then are of two kinds: for some are against the glory of the Supreme Being, and assail That Substance Which transcends all, as far at least as regards the purpose of the contrivers of them: while other offences happen from time to time against ourselves, and proceed no further than to the injury of some of the brethren, who are our partners in the faith. For whatever heresies have been invented, and every argument which opposes itself to the truth, resist really the glory of the supreme Godhead, by drawing away those who are caught therein from the uprightness and exactness of the sacred doctrines. [Matthew 18:7] And such were the offences concerning which the Saviour Himself again somewhere said, “Woe to the world because of offences! for it must needs be that offences come: but woe to that man by whom the offence cometh.” For offences of this kind, caused I mean by unholy heretics, are not levelled against some single individual, but are aimed rather against the world, that is, against the inhabitants of the whole earth. And the inventors of such offences the blessed Paul rebukes, saying, “But in thus sinning against the brethren, and wounding their weak conscience, ye sin against Christ.” [1 Corinthians 8:12] And that such offences might not prevail over the faithful, God somewhere spake unto those who are the ambassadors of the upright word of truth, and skilful in teaching it, saying, “Go through My gates, and make a pathway for My people, and cast away the stones out of the way.” [Isaiah 62:10] And the Saviour has attached a bitter penalty against those who lay such stumbling blocks in men’s road.

Haydock's commentary quotes venerable (is he not a saint yet?) Bede as pointing out the similarity in words used in the parable of the lost sheep

In the same way your Father in heaven is not willing that any of these little ones should perish. > Matthew 18:14 NIV

Here, little ones means sheep, which usually means whoever follows the shepherd. The shepherd being Jesus. The key component of sheep-hood is obedience and humility (at least the humility of knowing you're a sheep)

But, more to your question, there's nothing wrong with having lots and lots of explanations of the Bible. I think that Jesus is talking about real children here because He taught with examples all the time ("see that poor woman over there, she gave more than you bums"). So, the literal interpretation is little ones = little people and that should do a little to give any pedophile priest a bit of pause while reading that Gospel.

The metaphorical sense is that little one means freshly minted or potential Christ follower (which would include children) since hindering these folks on their spiritual journey could have gave consequences grave punishement is afforded the purpotrators.

The moral sense of "little ones" might be that little ones are those that it is incumbent on all the teachers of the faith to pass on to their students authentic teaching that will not confuse them or encumber their spiritual growth.

The eternal sense tells us of the punishement due to those who were given much but stink at passing it on. Which is why I approach each year of Catechism Class with fear and trembling.

If you look at Wesley's Explanatory Notes,

Wesley's Notes

17:2 Little ones - Weak believers.

However I would be interested in seeing what Hermeneutics says about this one too. I suspect that the original words can be translated a little differently - but similarly / same meaning.

Matthew 18 also cites Jesus' words regarding little ones, and does so more frequently:

At that time the disciples came to Jesus, saying, “Who is the greatest in the kingdom of heaven?” 2 And calling to him a child, he put him in the midst of them 3 and said, “Truly, I say to you, unless you turn and become like children, you will never enter the kingdom of heaven. 4 Whoever humbles himself like this child is the greatest in the kingdom of heaven.

5 “Whoever receives one such child in my name receives me, 6 but whoever causes one of these little ones who believe in me to sin, it would be better for him to have a great millstone fastened around his neck and to be drowned in the depth of the sea. Matthew 18:1-5

In this context, Jesus specifically identifies a child and speaks of children, then refers to children as "these little ones". So, interpreting Scripture in light of Scripture, it is pretty conclusive that "little ones" refers to children.