Still, are these two transactions because its a CoinJoin/Mixer TX or is this a single one? OP will have to decide what they want to see as what. Once they have done that its simple to write a few lines script that will answer their question.
Yes.
I only want to say that the original task is not unsolvable.
It can be solved. Not exact, but with some assumptions and defined accuracy.
Usually, we do not need the exact values.
I think that the answer
"There are N%...M% transactions transferring less than $100 and the probability is X"
may be acceptable