Any way to edit MC's head (hair,eyes,color?)
Probably yes, but there's a few reasons not to and pretty much all of them come down to the engine/how the game's designed.
You see, the images (animated or still) in the sex scenes and events are from many other games, but the named NPCs and randoms are categorized based on age, size and colour (hair, possibly eyes). As such, images for those events and during dates/sex change depending if the MC is male, female or futa (although there're many overlaps if the genital isn't seen with futa MC). The pics are then chosen, obviously, based on the other, random party.
As such, if you really want to see a difference and be consistent, other than changing the MC's paper doll, you'd also need to find images for pretty much 80% of the game and either colour the MC in them or switch them outright, keeping in mind the other party.
The reason the MC looks like the standard hentai MC or Female teacher should be obvious at this point.