So some more Momiji thoughts and findings.
So I'm finding that Momiji may not actually have to play a game of trying to get in as much of her mid-range tools are fairly potent stuns and interrupts. She's more or less a character that doesn't really have to play the stun game, so in that sense, she's similar to Kokoro, Hayate and Rig.
The one issue I've found is that she's got a terrible mix-up game, but that may not be too much of an issue as I originally thought. Her defense is average, as is her offense, but she has a lot of quick stuns and a number of fast and easy launchers. All she really needs is to interrupt, or put some light pressure (and she can do this through her three guard breaks or through some evasive stuff) and she's back on the offensive.
What I've found is that 7P is a great move to put some distance on your opponent and get you into optimum range for Momiji's rather good kicks. 4K is fast, safe on block and gets you +6 advantage. H+K and K are both 12 frames and both high, but I like H+K more due to its tracking and higher damage. Meanwhile, K seems to be more a move to create some spacing. Generally, if opponents tend to have a lot of evasive and tech crouch moves, H+K and K are pretty useless, but 4K pretty much covers that except in some rare cases like Lei-Fang's 1P evasion. 4K may even be able to catch Helena's ducking in her stance, but I'll need to check this out for certain.
In Ultimate, many character's standard holds got a major buff in damage. Hi-counter holds being able to due as much as 80 in some cases. I've found that Momiji's 6H and 1H holds for kicks are a bit on the weak end, but I did find something interesting...
If you did Momiji's Combo Challenge then you know that you can get a Power Blow off a low kick hold. I found that you can also get an Tenku P (that's Double Jump P). This leads to a big bounce stun that you can further combo from. Highest damage I was able to pull from this was around 48 to 55 damage using the stand 8P 6PKKP combo. Maybe you guys might find a higher damage combo.
Aside from that, I haven't found any good critical burst combos yet. It seems like her Uzukaze (single jump) PP can force a red critical stun through some combos, but I'm unsure if the opponent can recover in time before P+K.