You do realize that you can tell Jenna about either Katie, Lily or Debbie (depending on your choices) in ch21, right? And she's still fine with sharing you with any of them as long as you're being honest with everyone... The thing is, if you're shooting for the 4 of them, you'll be romancing Katie too and she's the default option in that case, but if you're not romancing Katie and instead are romancing Lily or Debbie openly, Katie mentions the one you chose and Jenna asks about that one.they may know each other but they practically never talk about each other
how many times does Jenna mention Jolina? at every opportunity, even the least appropriate ones
How often does she mention Lily or Debbie? never.
while for example the "sexual" hints between Katie and Jenna have always been there, am so promising, but they had been there before
this could be a clue
then for charity if we find it under the tree at Christmas we will unwrap it
The point is, again, Jenna knows them and doesn't mind if it if you suggest sharing with any of them... so the possibility of that poly with Jenna, Katie, Lily & Debbie is indeed there... it might not happen, it might be a long shot, sure, but like I've been saying Jenna is completely fine with all of them (and with Jolina).
I think it is an omission that Jenna doesn't share any real screen time with Katie & friends (at least so far) except for that phone call (after the 4some) where she clearly talks about them and basically shows that she knows them very well and vice-versa, but it is what it is, the majority of interaction in Jenna's side of the story are with Jolene because of the whole "hacking" plotline.