Many thoughts here, high up on my list is how happy LuoLuo was to be helping Song Li out like that - genuinely happy and even excited to be able to look after her. And how much it deflated her when Song Li told her she wasn't needed . . .
Given that would have happened before Hu LuoLuo moved out the first time, it feels like that may have played a significant part in her decision. Song Li chasing her down and re-initiated contact may be what made her rethink things, and decide to reset their relationship - realising how much she cared for Song Li, but also how brittle their relationship was, leading her to decide the only sane option was to start again on firmer ground.
Of course, the fact that this reset happened right at the time that Song Li finally figured out her feelings made it rather more difficult for LuoLuo to reset things the way she wanted - Song Li isn't the kind of person who'll accept being told "we need to just be friends" when she wants to be so much more . . .
Because one thing Chilly is definitely right about is that Song Li is selfish and self-centred. Not because she's a selfish manipulative narcissist (which is the unkind way of saying what Chilly seems to be suggesting), but because she's always been on her own - she was on her own even when her twin was still alive, because they were such different people who don't seem to have been able to connect as friends even though they were close siblings. Outside that, she doesn't seem to have connected with many people at all - her editor is clearly a friend, her agent is . . . not so much, Song You is a kid, and one that she doesn't connect with all that well even though she clearly cares about her (Auntie Carrot definitely wins that fight hands down). Song Li has never had to be considerate of other people in any emotional sense, and as a result she's never figured out how to do it.
She does seem to be learning pretty quickly, though, now that she's realised she does actually care rather a lot about about Hu LuoLuo.
Which is why I definitely agree that Chilly is shooting herself in the foot here. My reading of this situation is that Chilly wants to make Song Li back off from Hu LuoLuo, by showing her that there's someone who's wise to her game and willing to protect LuoLuo. The problem is, in the process of demonstrating that she's wise to Song Li's game, Chilly is actually handing Song Li a pretty solid lesson about how being selfish and inconsiderate can really hurt someone who's just trying to be helpful. Song Li is taking that lesson and running with it, right into Hu LuoLuo's arms . . .
And unlike most useless lesbians, Song Li is an author - she has all the words, she can even line them up neatly and give them a good polishing. For once communication probably isn't going to be too much of an issue . . . at least, until LuoLuo needs to find words to respond with . . .