I still have no inputs about the origin of this practice. I still don't have no answer. Regarding ladies chanting and reading a part set for the reader, well initially when ladies began singing Fathers objected saying it was too sensual and that they sang in a too emotive way (and at this time Russian polyphonic music , that I dislike by the way, did not exist!). I think that they sing and read because there is a lack of men doing it.
It seems to me that globally at church, the man comes first and then the ladies maybe because of the role of Eve. If you go to Georgia for instance, which is, according to me one of the last traditional orthodox places in the world (whether true orthodox or not), you'll see that after children have communed, men will go and later ladies. It will be the same when times comes to venerate things during a service, to kiss the Cross, take antidoron etc. To be honest, I've seen reports about this in Romania too... An advantage of this, is the absence of traffic jam at church with everybody rushing to the same place at the same time. The fact of having girls throwing petals would be a sort of inversion of the classic order of man first, ladies after, and giving a sort of privilege to ladies.
But I agree globally with you: it is not a casus belli
