Since CH 4.5 ended (for those on the Bella path) with a Bella visit, an MC/Bella meeting/conversation will likely start CH 5.
We know that Nia called to reschedule her visit with the MC from Sunday to Saturday so this will likely be a significant part of CH 5 as well.
Beyond that, it's hard to say since Ocean is still working on CH 4.5 Final.
Some other reasonable possibilities:
Zara calls to tell the MC to meet her for training.
She likes him and this gives her an excuse to spend time with him as well as test his resolve to train hard (which will help to show her he's worth her time and affection or he is not).
He also owes her an answer supporting the prank against Melanie C and this conversation where Bella confirms that Melanie C is a Bitch who deserves it could happen at the beginning of CH 5 (this could also include a chance for Bella to team with Zara and the MC to go after Melanie C - which could lead to some sexy bonding with both women in the future -- hey, a guy can hope!
).
A possible cliff hanger could be when Ayua shows up at the end of CH 5 to spend time with Bella and the MC (regardless of the path, Bella kiss yes/no, Ayua asks Nami what makes the MC so special; she is both curious about the MC and happy for Bella).
Bella is one of Ayua's BFF's, along with Nadia, and she has to be back sometime Sunday for the sparring session with the MC so, if Bella leaves her weekend gathering early, Ayua could as well.
I see some Bella/MC content regardless, unless you are not on the Bella path.
CH 4.5 Beta was heavily focused on Vic, Mila and Nami but it still included two key Bella events - the Melanie C. reveal from middle school as well as Bella showing up at the end of CH 4.5.
She could be part of this next update in the same way.
In CH 5, Ocean is also implementing a phone with new capabilities that are not present in CH 4.5.
A video call with Bella (not sure if the phone can simulate this or not) or a phone call similar to the one between the MC and Bella when the MC was with Noji and Nami visiting Nick could certainly give us some reasonable time to build the Bella/MC relationship.
I could see the MC starting to text Bella and then she just calls him mid text and, when he comments that 'we were already talking via text' Bella could simply comment 'Now I get to hear you voice as we talk.'
I see many possibilities like this to build their relationship and I can see these sprinkled through those updates without a heavy focus on the MC/Bella or a major MC/Bella scene.
We'll know more once we start with Dev diaries for CH 5, with the first one likely hitting in Jan 2023 once CH 4.5 has gone final.
It's always good to remember that he is developing WIAB concurrently with SG so development may seem to be slow, but he is actually building two major AVNs simultaneously.
