My thoughts on Lum after playing a bunch of matches.
Jaina - At least 7-3 Jaina. This matchup is ridiculously bad, maybe even 8-2. Lum has to go crazily offensive vs Jaina because her ranged game completely shuts down his items, and with no move that has any projectile invincibility he just doesn’t have the tools for it (yes, there is a very small window in the middle of the animation where ground B can go through an arrow, but it’s very small and if you mistime it you’re taking a lot of damage). He needs like 5-6 correct guesses per round to win, whereas she only needs 1 or 2. Basically every round is decided within the first few seconds, if Jaina gets a good hit and pushes him away, he’s not coming back. IMO, this is likely the worst matchup in the entire game.
Midori - I suspect this is 6-4 Midori. The strategy for Midori here is just to pay super patient and get Dragon form. Once he’s a dragon, he can press the advantage super hard due to Lum’s poor reversal options. This forces Lum to rush down when he’s not in Dragon form to try to kill him faster, but counter is a very strong option when he does this.
Setsuki - Probably 5.5-4.5 Setsuki. She has great tools to get in quickly or get around his items, so their usage is limited in this matchup, and Lum has no good tools to get her off him once she does get in. In particular, I feel that this matchup is quite a bit harder than vs Val.
Rook - I feel like this is 5-5, maybe 5.5-4.5 Lum. Lum has good keepaway vs Rook and his Air B breaks armor, but he has very poor reversal options so if Rook does get in, he can quickly die. Rook also hugely benefits from cherries and cake, as his ground super is very powerful in this match and it’s a battle of attrition with him anyway, and his ground punch is good at collecting them. This is definitely much easier than vs Midori, though.
Valerie - I believe this is probably 5-5. Like almost all of Valerie’s matchups, her buttons are stupid good, but if the opponent gets one good hit she’s almost dead. In particular, I feel like Lum’s supers are very scary for her, because they force her to ease off on the offense for a second and she can easily die from it.
Grave - I’ve only played this a couple times. I suspect it’s probably 5-5 or 5.5-4.5 Lum but I can’t say for sure. I did notice that you have to be very careful with your wind usage in this match, as you can easily blow yourself into items or other bad situations.
Geiger - I’ve only fought this once and the Geiger player wasn’t very good, though I feel like Geiger has the tools to shut down most of Lum’s shenanigans. No rating for now but probably near even.
DeGrey - probably 6-4 Lum, possibly even 7-3. Lum’s easiest matchup for sure, I don’t think I’ve ever lost it. DeGrey’s forward movement is slow, so if there’s any kind of space between them, Lum is very free to throw items, and items cause a lot of problems for DeGrey. His only hope in this matchup is to push Lum to the corner, but it’s a struggle for sure.