I like being honest with people so here it goes:
I think developing another project while your main one isn't done halfway or 3/4 of the way is a grand mistake. It may look enticing but you get into a hole which LOT of developers dig themselves into.
Is developing games your fulltime job? From numbers I'm guessing you do this as side work. I know development of Sunset Fairies has been going on for a while but splitting your efforts between TWO projects is going to diminish both. More so when your main game has an insane potential.
You may end up in a situation where both project become chores that you have to finish... or abandon. Combined with general disgruntlement of people who are there for one project and not the other. I understand the general temptation to start something new... but at the same time, you could push potential of Sunset Fairies to its maximum potential.
What I mean is - aggressive advertisement of the game by utilizing similar sites to Lewdcorner. Hell, maybe even doing a patch for certain sites which makes the content more... acceptable, shall we say. Then posting same content on r34-like sites with proper advertisement in source and comments.
Then if you're in a mood to actually make something more hardcore... well. Sunset Fairies is set as a corruption story, right? You can always incorporate some hardcore elements into it too as optional fetish content. Possibilities are endless. Developers who
actually finish their games are held in greater reliability and trust too.
As for feedback on topic of The Wild Boy:
1. Concepts for the characters definitely need more varied body types. Having ALL thicc busty women is... kind of a waste for possibilities? Would be kind of same-y for the scenes. I feel like lot of the inspiration went from doujins of Shota x Female

One of the prime examples of what same body type game looks like would be Restore Her Career. Awesome game but every character is in essence the same taking away from the variety and believability.... as not every person out there is a thicc big boobed milf even if you won a genetic jackpot.
So yeah, different body types and proportions. Different strokes for different folks as they say.
2. It would be good to actually explain some of the tags properly. For example horror? Bestiality?
Alongside explaining general premise and "road" to a new game. One of the best ways to sell people on the story is to explain what the general progression is going to be and what you imagine end road being.
3. I think one of the great decisions you could do for health of the game is to take one of the sisters and make her into a loli. Actual loli that sort of matches MC's age. Be it year or two younger or older. Not a teen but an actual loli. Shota on loli is pretty rare. Combined with planned hardcore tags? Bingo! Have her be born after the MC's disappearance or be his somewhat older sister.
That way, lot of people who are out there for the more taboo games can jump into it for snippers of the younger sister content. More so when you've built your audience from a loli game. People would have easier time adjusting and moving to a new project.
4. I legitimately think one of best starting points for corruption would be addition of a non-related teacher. Shota x Teacher is a certified classic. Unless of course relatives take that role. You know, teacher is hired to help MC integrate into society. Over time she either tries to help or gets dominated by MC into sexual situations.
Either way, no matter what you decide to do, good luck and much love!