You left out Cath and Daiyu's Client, who are very probably the same person. I think she's more likely to be included (regrettably!) than a dwarf girl. And we don't know what will emerge from ED's egg. Probably a boy since it's Nergal's future vessel, but Tinkerer has said gods aren't limited in how they manifest...
I'm hoping for an expansion once the Main storyline is concluded. And a redesign to resemble the various recipe books would really open up the BoG's capacity. But I'm not going to bitch if it doesn't happen.*
From a
purely story perspective, I like the idea of a desirable, fleshed-out** female character the MC cannot add to the harem. Or one he can try to get but it always ends in Game Over, no way to salvage it. Flirting and maybe some "if things were different," sure, but unattainable. I think the Baron's wife fits that role best. But given the nature of the game I kinda doubt we'll get one of those.
*Something I'd like added to the BoG regardless is what bumps their Affection other than sex & sleeping at their place. Specific things to gift, buying pastries from Rosy, cooking meals for Mia, etc. Maybe they don't show for a girl until after the first time the MC has gifted/done the thing.
**Siv and Mrs. Miller aren't fleshed out. Greta and Makith aren't desirable to enough players to make it worth the effort IMO, fewer than with Maghda. All of them would need new content past what is already planned.