Pinups were recently buffed, and as Ellen will tell you, outfits that you put them in will increase the price. That price changes for each outfit so it is up to you to find the best outfits to sell for each character. Or you can just do deliveries. But double pinups with Felicity and Emma sell for $175 at most, which is massive.
Explore content is already apart of the story, but I think you mean "bringing the main characters into the explore content". If that is the case, I will say that the point of the Explore content is to treat the world as a character. This is why main characters will never show up in Explore content. But main characters currently do go to the areas in the Explore content in their story and repeatables.
Harem Hotel is not a polyamorous story. Harem Hotel just includes a polyamorous relationship, which is no more inherently sexual than a relationship with two people. Since most stories with married people don't include sex, I think we'll be fine ;) Making all sex optional is easy and only a good thing though. You could avoid sex with anyone you don't like, or any sexual option you don't like. Anal was already always optional, but now blowjobs and vaginal will be too.
Making it all optional means it's not too much harder to release a SFW version which could be played on Youtube or Twitch, or anywhere else people want a story. Our society hasn't accepted sex work as real work yet so we have to bend over backwards to fit in. I can't even get some platforms to acknowledge my existence.
It's pretty much only itch, and maaaaaybe Steam. And these are only recent advancements.