What are some sources of March, 25th being the date of the creation of the world, or of the creation of Adam and Eve, or of their disobedience?

Up until the first Passover in Egypt, the Jewish first month was Tishri, being about September. That was considered the creation of the earth and Adam/Eve.

2. this month [Nisan] shall be unto you the beginning of months--the first not only in order but in estimation. It had formerly been the seventh according to the reckoning of the civil year, which began in September, and continued unchanged, but it was thenceforth to stand first in the national religious year which began in March, April. Jamieson

See also this.

So, one would search in vain for an answer to the OP.

To get a better understanding of this, one must realize that in the Middle Ages people more willingly accepted tradition as being true. Pious traditions or legends were told from time immemorial were simply believed.

It seems that the number one source of your pious legends comes from the Golden Legend by Blessed Jacobus de Voragine (1230-1298).

Blessed Jacobus de Varagine or Voragine (Italian: Giacomo da Varazze, Jacopo da Varazze; c. 1230 – July 13 or July 16, 1298) was an Italian chronicler and archbishop of Genoa. He was the author, or more accurately the compiler, of Legenda Aurea, the Golden Legend, a collection of the legendary lives of the greater saints of the medieval church that was one of the most popular religious works of the Middle Ages. - Wikipedia

March 25 according to the Golden Legend is rich in symbolism:

According to this legend, the Creation of Adam, the Fall of Adam, the murder of Abel, Melchisedech's offering of bread and wine, Abraham's near sacrifice of Isaac, the Annunciation to Mary and Conception of Christ, the decapitation of John the Baptist, the Crucifixion of Christ, James' killing and Peter's escape all occurred on March 25th. - Davidlol

Please feel free to peruse the entire Golden Legend when and if you have the time to do so from the Medieval Sourcebook: The Golden Legend (Aurea Legenda) Compiled by Jacobus de Voragine, 1275 Englished by William Caxton, 1483.

Some “Historical” Dates in Medieval Liturgical Calendars from England may be of interest to you even though some of these dates are not the same, but are relatively close. For example, the Creation of Adam was on March 23.

He also notes the dating of the creation to 25 March as well:

The symbolism attached to the Julian date of the spring equinox was not limited to the Passion or Resurrection of Jesus. The Alexandrian monk Annianos, for instance, dated the creation of the world and the incarnation (or conception) of Christ on 25 March as well. The vernal equinox was associated with the creation as early as the third century, but opinions differed on the day of the week of the creation on which 25 March had to be placed: some preferred the first day (Sunday), when God separated light from darkness, others decided in favour of the fourth day (Wednesday), on which God created the so-called luminaries, i.e., the sun, the moon and the stars. ...

The idea that Jesus was born (or conceived) and crucified on the same calendar day, and thus lived a perfect number of years, is first attested in the Easter table of Hippolytus of Rome (AD 222). - “Historical” Dates in Medieval Liturgical Calendars

Hippolytus's Easter table has ΠΑΘΟϹ ΧϹ (the passion of Christ) on a day on which the 14th of the Paschal moon falls on Friday, March 25th.

The computist of AD 243 says that the world was created on March 25th, and that Jesus was born on Wednesday, March 28th, the same day that the sun and moon were created. (De Pascha Computus 4). But he says the crucifixion was on Friday, April 9th. (De Pascha Computus 9).

In a list of vigils observed by the church of Tours, Gregory of Tours includes a vigil of "the Resurrection of Jesus Christ our Lord, 27 March, in St. Martin's Church". (History of the Franks 10.31). The resurrection on March 27 presupposes a crucifixion on March 25.

March 25 was chosen for the creation of the world because it was the old Roman date for the equinox. The computist of AD 243 is explicit that the world was created at the equinox:

[Scripture] openly shows that this is the first day and its following night, between which the Maker of all divided irreproachably and equally. (De Pascha Computus 3).

The doctrine of creation at the equinox was held also by those who considered the equinox to fall on some other date. A homily of AD 387, formerly attributed to John Chrysostom, states:

For it is fitting that creation should be before all future time, and that when day and night first came into being, their extent should be defined equally. Then afterward, from motion, inequality should arise.

This homilist considers the date of the crucifixion to be March 25th, but March 25th for him is "after the equinox".

The Venerable Bede also considered the creation to have happened at the time of the Spring equinox. For Bede, the world was first created on March 18. The sun and moon were created on March 21, the equinox.

Not until the fourth morning did the sun, rising from the midpoint of the east...inaugurate the equinox....The moon, on the other hand, was full at sunset, for the Creator, who is justice itself, would never make something in an imperfect state. It appeared...in the mid-point of the east, and stood in the fourth degree of Libra where the autumn equinox is fixed. (De Temporum Ratione 6).

But he acknowledges that "some have claimed that the first day of the world was on the 8th calends of April [March 25]" (De Temporum Ratione 6).