Is there sharing with the other girls too or just the main one?
It's a safe assumption that if you pick the sharing or open-harem option the other main girls will potentially do stuff with other harem members (based on dev previews the first opportunity to start some internal harem sharing is coming very soon). I'm not sure if the girls other than Val will be interested in non-harem members though, as you said.That is a very good question, but thus far, there isn't any indication that the other girls would be into it. Valerie is a special case because sex to her is basically food. The other girls may feel differently.