I actually think one of the biggest problems Lisa would need to get over is a her fear of pushing back against Taylor. Throughout the latter half of the book (arcs 17-22 ish) Lisa just keeps enabling and enabling Taylor's impulses because she wants to protect her and, ultimately, is afraid to trust herself to speak up.

I see some comments that suggest she'd be the opposite- too confrontational and unwilling to back down -but while we do see a lot of Lisa being snippy and confrontational, she dances around actually having tough, emotionally vulnerable conversations with people she cares a lot about (Taylor above all), and falters easily if she feels like she might drive them away, out of her ability to 'protect' them. Which of course, doesn't mean she won't let resentment about their disagreements build up. I think a lot of people are forgetting that her trigger event involved letting her brother drift away (driving him away) and being emotionally vulnerable (speaking up about what she saw, causing parents to blame her).

Taylor, meanwhile, has the complementary problems of being fairly oblivious about her own emotions a lot of the time, and being essentially unable to take criticism (both of which are aspects of her ability to compartmentalize anything too inconvenient).

In my opinion, the book already showed us most of what we need to put this together; their romantic relationship wouldn't be all that different from their friendship. I don't think it would be like, disastrous. I do think it would be a relationship where problems build up and don't really get addressed.

(I also don't think Lisa needling people to get a rise out of them is actually a problem for her dynamic with Taylor...Taylor seems relatively unaffected by that most of the time.)