Maybe they're doomed, but its what a lot of people want. Or at least they want something that feels like Rainces version, but that actually gets somewhere. Somewhere real, and not game over sex or stuff like that. And that does it sometime soon, because I for one don't want to wait for more slow burn only to have Zip disappear a few months down the line before anything happens.
It depends on what the pervy photos are and Liza's interest in keeping them secret, and what Bobby can do to add to it on his own. Adding in a friend would imply a fair amount of work and delay to do it right and to set up everything, and there are those who would begrudge the new character being added. I'm not particularly interested myself, but others might be. I'm not saying it's not a valid path, but given a choice between going down that route for a payoff further down the line with Liza, knowing full well Zip could lose interest at any time, or a payoff sometime sooner via the direct blackmail route, I'd choose the latter.
She could go that route, but if she's wrong, then as you said, her reputation is destroyed. She doesn't hold Bobby in high esteem so she doesn't necessarily have a reason to believe he won't tell. She may see it as far more unlikely that he'd actually try to have sex with her. The second is more in keeping with porn game logic at least, while the first is more real-world logic. Both have their risks, but story-wise I'd choose the one that leads to sex with Liza sooner. Maybe its a bit of a cheat story-wise as far as believability, but that's kind of standard in these types of games.
Speaking of story-wise, I cranked out a little fan fiction to go with the original photo where Bobby just decided to pull down Liza's shorts and have his way with her. Not sure if its appropriate to post or link to here though so I won't, but I did enjoy writing it. It plays to my preferences, which is of course what I'm hoping this game to do even if I'm just one person and one viewpoint. But you're doing the same, as are countless others and Zip themselves. It's hard to create a game as it is for someone like Zip, especially when it's a remake/continuation of a game like BBS. There's a lot of expectations that go with it, but also people wanting things to be changed in some cases, but not being able to agree on the details.
At the very least I'd like to see the sex happen we get that opportunity even if the updates stop coming after a while. It doesn't have to be the end of Liza's route necessarily, but it would be moving it into the next phase. Her ongoing story post-sex with Bobby could be ongoing in the background as things progress with the other love interests in turn. I just don't want to invest more time in another version of BBS only to be ultimately blueballed. Maybe not literally, because I've cum to this game many times. But I want to not be blueballed mentally or emotionally by not getting a satisfying, "real" sex scene with one of the main characters.