you guys seem to be forgetting parou is gay, regardless of how it came about. so, yaoi. he only dressed as a girl for the guy he liked. and technically, ryou seems to find his attraction to marika for her femininity so not like he's really gay. and regardless of what marika feels on the inside her body is still a boy's til that gets changed, so even if it'd be marika x some boy having sex, physically it's still 2 boys. so that also, partly, is still yaoi.