for me it's okay as you say, as long as something happens
Between her and Jessica, I think something further will happen. Maybe one will invite the other out for drinks as "friends", and it will lead to them either getting it on in the bathroom of a bar, or going back to Shani's place.
Shani and Blake are, at the moment, the most viable lesbian endgame paths for Jessica because Heather's not leaving Christian for Jessica, Rosa's married, and nothing's happening with Eve and may never happen, so it just leaves those 2. I've always been a Jess/Blake fan, but Shani's now jumped ahead in terms of action with Jessica, so Blake needs to catch up.
I think that whatever Shani does would be left as a choice for the player, hack even at the pool scene we can choose to invite Coner or not, so I believe we will similar choices in the future. If players want Shani to stay pure lesbian, she will and if they want her to be advancers in her sexuality she also could.
The opposite is equally possible, that Shani will automatically shoot down any potential future threesomes by affirming to Jessica that she's not into guys and putting her on the purely lesbian path, which is what I feel is more likely.