Hi!
Yes, traps is a feminine men/boys. I'll try to explain how it works in this universe (in my mind :D)
There is like 4 genders. You can easily identify the futanari or the woman by the obvious reasons, but to identify the trap - you should eximine yourself because it's not easy to distinguish the usual man and a trap, because all we growing different.
Think about it like.. the traps - it's naturally weaker version of a man with the feminine traits.
Actually traps there could be heterosexual, but probably it's something unusual.
No, there is no transformation in this game. I agree that traps !=trans