People would rather know before playing, to save time. (it is a finite resource).
Why all the concern? Well many have been screwed over by other devs... which obviously isn't your fault, but.. well, once burned, twice shy.
The answers clear it up pretty well, just to clarify on these:
1. Wouldn't it be safe to assume the son is basically the protagonist? and that you just show perspectives of the others?
3. So basically just nude viewing? or is one voyuerism MC watching the girls get it on? (cause depending on how you do that, it could be lesbian based NTR)
4. Will the lesbian content be avoidable? and will it be with or without MC knowing and/or without his consent? (cause if without then would be NTR).
Personal suggestion: I suggest making lesbian content avoidable, just so you can reach a larger audience/demographic, since they are similar, but some people just don't like and even hate lesbian content. (especially the NTR kind where the sister goes behind MCs back... is done more than you'd think).
Only if you wish to do so though. If not, I would add a note that lesbian isn't avoidable, so those that don't like don't complain. (and if they do, then you can point to that statement, and blame them for ignoring it
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