I think some of Julia's struggles this season just have to due with getting older. And I don't event mean physically growing, though she has grown since last season (still is really tiny though), but a 13 year old mindset is very different from that of a 14-16 year old mindset, when along with the physical changes of puberty a lot of girls start to doubt themselves, suffer from poor self-esteem, become very sensitive and perhaps over-critical. It's a quick shift but most girls go through it, being a bubbly young tween without a care or fear in the world and you just go for everything and are cute and soak it all in then all of a sudden there are expectations and everything, your body, your thoughts, emotions, etc. change and it's hard to deal with. We saw that happen with Mirai and Caroline a few years back, and I think that is part of what has caused Adelina to struggle, she seems very eager to please, and a bit self-conscious, very hard on herself, and I think that makes a big difference.
Liza seems to have the great characteristic of mental fortitude and competitive spirit. She wants to do well and showed she has what it takes, proving all the naysayers wrong who thought she wouldn't be able to jump now that she has filled out. To me it seems like Liza is very focused on herself and not as distracted or affected by things going on outside the skating rink. Anyways her body is just going through a transitional period, she is still quite a small girl, short and very small frame, her legs, arms, and waist are just now thicker which is common for girls at that age, most likely the weight will shift as she grows into a more womanly shape. Based on the way she skated today I am not that worried about puberty monster doing her in, her good technique has served her well, this is probably the most difficult time she'll go through physically, and despite comments of others if you look at pictures of her in normal clothes, you'll see she really is very tiny. I don't think Liza is even 5 feet tall so on one that small a few pound gain seems very noticeable. As for Julia she has no speed going out of her jumps, and the technique isn't as good as Liza, I worry more about puberty hurting her jumps even if she remains slimmer than Liza.