I can see that one working if Jet builds up on what was shown when the MC first started working at the nightclub.
Might take a bit more build now as that was some time ago. It did look like the Anna/Cathrine thing was going to go somewhere then it switched to just Anna. If played right it could go okay, I think anyway.
I do agree with Jane and Nicole. I can see it working as a one off scene or brief thing but not sure about a full relationship.
The dev said no incest, the show was intentional.
What some of us find hilarious is even after being told it's never gonna happen some people can't let it go.
It's starting to look incredibly desperate.
You're only being cucked if you can't accept what it is and move on, that's all on you nobody else.
(I suggest reading the whole thing, to get the idea of what I am trying to say, as I believe any single sentence on its own would be out of context..... I suck/excell with interconnected writing where it falls apart without a certain sentence or piece of text)
warning: wall of text, proceed with caution
It is still a little stupid to show off that character model, because now they aren't just cucking the incest crowd but also people who just find that model hot and want the MC they play as to fuck them. Sister or not the dev is just being a bit of a cunt lol (positive cunt here btw, imagine it with an irish accent, all nice sounding). Although imo that makes me like the dev a little more, cause people without a little bit of cuntness are boring, although I would withdraw that sentiment if the dev literally cucks you with that character cause there is being a bit of a cunt and then being a shit cunt (negative scottish cunt with a hard unt), the latter would apply if they did that, cause would just be disrespecting the player, unless you are into NTR and it is optional, but forced would be massive cunt move.
I myself just want to see MC fuck the model, while i do enjoy incest content myself would be more than happy if the dev switched the models of Jane and Julia just so that it isn't incest anymore because that model is hot 
Also lets be real it could just be "no incest" cause of patreon overlord paranoia (a valid paranoia though), and a "fan" that is totally not the dev makes a custom addon that is that content. I wouldn't be surprised personally wouldn't be the first to do a patch. Also the Dev might be considering just not giving any promises but just toying with the idea and testing the waters (Is what I would do if I was unsure, aka would say nope not gonna happen, that way I don't get anyones hopes up, and if I do happen to do it, will be a nice little bonus surprise).
While I am not saying they should pander to any particular crowd (incest crowd, cuck crowd, vanilla crowd (yes they count as a crowd too who realistically get the most content
)) they shouldn't actively try to piss one off because what you will find is they typically blend together (e.g. a large portion of the vanilla crowd are also in the incest crowd and vice-versa, not so much for cuck as that is much more niche and has quite a bit more stigma.... imo well deserved but lets not go there XS < just my opinion here ignore it) which would piss off legit fans who are into incest, but don't care about there not being incest, and thus don't deserve to be beaten over the head with that fact. Remember those who are vocal are always the minority of those people and should not represent them, most people who are into incest games just get slightly annoyed with stuff like a obvious incest-pandering game without incest (not this one of course) and move on, only a few bitch and moan immaturely, the rest (aka the majority) shouldn't be punished as a result.
Note: on that last point am not saying the dev is punishing them, atm just some teasing, don't matter still nice to see the model at least.
Just my raw unfiltered 2 cents on the topic. I myself think Lisa is bae. and my save name is aptly titled "You are tearing me apart lisa." (for the refence

)
P.S. tbh the dev teasing the sister like that is the reason for people on both sides getting pissed off about the topic, if they just said nope and only showed for dialogue there would be a lot less but because of the tease this stirs up those who go "INCEST IN EVERYTHING BITCHES!!!!!" and thus pisses of the "STFU stop spamming thread they gave you an answer." crowd. that being said the dev ain't responsible just cause and effect. I would do the same hehe (to tease a little not stir shit in comments sections).
P.P.S. maybe there should be a disclaimer on the main post saying in big bold letters "NO INCEST CONTENT EVER!!! stop spamming" that way it is made pretty clear instead of some obscure comment somewhere.... just a thought.