Both slots can be anything if no major body type changes involved.
For both different crotch area "configurations" are included as alts.

Originally I wanted to make two slot auction, but at the final moment I decided against it.
I mean, for example, if I'm bidding for a blue slot, I kinda want to know who'll be in the other one. Or at least what they will be packing. I mean sucking strangers may be good and all, but it's definitely not for everypone.

And yes, originally-originally purple was Twi. It still can be Twi if you want to.