I have a feeling that something is going to happen with Calypso this update. Not necessarily a full blown H scene but MC connecting to her during the "bleeding" segment at the gas station will probably be explored a bit and Calypso will take some interest.
Now let's do some analysis with the most pitiful dataset in existence and while taking too many liberties:
Of the main girls, Annie's scenes had the least distance between them (5 scenes passed from Annie's first to second), and Penny's had the most (8 scenes passed betweer her first and second).
The average time between a girl's scenes is 6, meaning that once we see a new scene, there will be 6 more scenes till we see her next scene.
The first two releases had 2 scenes each.
The next two had 3 scenes each
Chapter 5 had 4 scenes so it's possible that 6 will have 4 too.
I'm expecting that the next scene we will see will be under "Others" and I'm hoping it will be Calypso, unless she is made into a main LI.
Next in line are Dahlia (6 scenes since her second), Annie (5 scenes since her second), and Alex (4 scenes since her first).
So if the pattern remains somewhat consistent, I expect to see these 4.
As far as previews go, we saw these in a more intimate setting
Alex (both in Eternum and in what seems to be her new flat)
Nova (I guess that ass in red is hers, and we see her in underwear)
Annie (seems to have some time alone with the MC in the house, although it's not necessary that the 3 renders are connected).
Penelope, Calypso, Dahlia and Luna's shots don't seem very intimate, so at the very least, the chances we will see them in an intimate setting are less than the other 3. Nancy had her fun recently so I don't expect a second one that quickly.
Combining the two, it seems most likely that we will see Alex and Annie and there is greater chance for Dahlia, Nova or one under "Others".