Sister harem would be pushing the boundaries for Patreon, so that's a no go.
Also, any harem featuring Alexis and either Minami or Morgan would be kind of tough to justify, as both Morgan and Minami have Alexis on their shitlist for the way she treated the MC back when they were originally dating.
Not saying it's not completely impossible, it's just one of those potential harem scenarios that is going to have a harder time to write and make sense.
As for Kylie not being a member of the home harem, I can see it as her getting quite jealous. The only harem Kylie's a part of is the Taming Harem, and that only kicks off when she tries to fight Ayesha, who is able to handily beat her down. Ayesha can fight. What about the girls in the Home Harem? Yeah, they might hold their own in a slap fight at the nightclub, but against Kylie's level of crazy? Bear in mind, in other endings, Kylie can potentially straight up murder and decapitate Bree or Sasha.