SPOILERS FOR ANYONE NOT FINISHED WITH 0.6
Also, just my own pure speculation/reasoning here...
Working through my full playthrough with the 0.6 update (gotta say, love the updated early dialogue to make things concurrent with recent world events, really appreciate that), and I did not realize that some scenes happened earlier than they did in my brain (Space Oddysey specifically, when we got the Midnight Cookies scene my brain was wondering why Cari was doing so many Annie scenes in a row, but upon replay, yeah, that was 2 updates back...).
Based on progression of each girl, as well as what has been hinted at occurring soon in the last couple updates, I think we can surmise what scenes we're going to get in the next two updates.
Each girl has had a scene approximately every other update (0.3 and 0.5, or 0.2, 0.4, and 0.6). Looking back at each girl's scenes, as well as where each one has been left off;
Annie has stated that she's ready for it "next time" but just had a scene in 0.6, which makes me believe we'll sleep with her in 0.8.
Nancy has only had two scenes, but the elevator was one of those. With her insatiability, I'm guessing we'll get a scene in 0.7, and I'm guessing we will release inside, if you catch my completely unhidden drift.
Dalia in 0.6 admits to herself she wants you to be the one, but like Annie, just had another scene, so probably 0.8 (I'd bet something to do with "the hunt").
Penny is a little harder since she's really only had the one intercourse scene (yes, she had the photoshoot, but that was more of a tease, like Dalia's Shower Show). I'm guessing we'll get her next scene in 0.7, but I don't know if it'll be full intercourse.
Luna. Sweet, poor, neglected Luna. Why, Cari? Why does she only have one scene?! She's overdue another scene, so I'm betting we'll see her in 0.7. However, based on her progression, I can't see this being full intercourse either, which slightly scares me for how late into the game we'll finally sleep with her.
Alex, I mean... We all finished 0.6. She's probably pregnant if y'all selected pregnancy options. I'm betting we'll get another scene in 0.8, maybe even a threesome with Dalia at that point? She's a shapeshifter, so her, Dalia, and MC teaming up for "the hunt" and it getting steamy is high on my list of scenarios that could play out.
Nova is a guaranteed hit for 0.7, full intercourse, probably going to lead to her getting pregnant. With you going to her house for "Netflix and chill" as well as her and your progression, this is the one I'm most sure of.
Now then, those being said, what about side characters (Sadly Calypso being considered one of those)? We've gotten one in 0.1 (ngl, this one was probably just to keep people around and not have the first 2 chapters only be teasing and the like, which fair enough, Eva is great, gave Cari time to develop the characters for the main girls), one in 0.3 (Still conflicted on how Ma'at's story is left, obviously we don't want anyone excommunicated, but Nova or someone (probably Nova) mentioning that Ma'at's account was banned permanently or something would be nice closure), and finally Calypso's in 0.6, which feels like the beginnings of her being our central "Other" girl. With all that, I could see Calypso getting a 0.7 or 0.8 scene, then finishing off with full intercourse with her in 0.9 or 1.0. With the story, I'm kind of doubting she'll be an endgame prologue girl, what with not existing in Kredon but I'd love to be proven wrong about that. Now that we've seen Eva again as well, I could see Cari slipping her in one more scene before the game is done.
There's also a trend Caribdis has set for number of scenes per update. We got 2 scenes in each of 0.1 and 0.2, 3 scenes for 0.3 and 0.4, and 4 scenes for 0.5 and 0.6. This gives me hope that 0.7 and 0.8 will each have 4 scenes, and 0.9 and 1.0 will have 5 scenes each, giving us 18 scenes total.
With all of these observations we can come up with the following rough completely theorized and hypothetical timeline for the next scenes;
0.7 - Nancy, Penny, Luna, Nova, ???
0.8 - Annie, Dalia, Alex, ???, (Probably Calypso)
0.9 - ??? x5
1.0 - ??? x4, (Probably Calypso)
If this holds true, we will have fully slept with Annie, Nancy, Dalia, Alex, and Nova by 0.8, Penny and Luna being left to have intercourse with. Assuming that, I'd guess all of the girls we've slept with by then would be pregnant (of the main girls), else they'll get pregnant the second time we sleep with them (presumably most of their second times would include multiple girls).
We've also been given a lot of hints as to the threesomes and beyond we will likely get, mostly between the sisters and Nancy, but with others thrown in as well. Annie and Nancy have a different bond, I could see that happening as a threesome, Annie and Dalia weirdly keep getting thrown at each other in conversation, mostly by Annie. Annie and Nova were very briefly hinted at by Harley, but that's it. Nancy has been hinted at multigirl scenes with her daughters left and right, there's Nancy and Dalia (rub it in Kai's face), Nancy and Penny, or Nancy, Dalia, and Penny (Rub it in Kai's face even more). I can see Nany initiating a lot of these as she herself has been the one flirtatious bringing them up. Dalia and Penny is just a parallel to the Lauren and Judie final scene from OIAL. Dalia and Alex has been heavily hinted at by both girls, so is almost a guarantee, as is Penny and Nova. Again, this leaves Luna as an outlier, but so was Rebecca in OIAL, so whilst I would like to see her getting involved in some scenes with other girls, her condition also makes it an easy way for Caribdis to explain why she wouldn't.
Again, sorry for the ramble, this game is just too good not to invest time and brain power into. I said it on my last post after just finishing 0.6's new content but Caribdis, keep it up, you're easily the best VN/ero writer/game maker out there at the moment, take your time with your updates to keep things getting better as they have been, just don't make us wait too long (I'll give you a year, maximum).