1) i don't think it's particularly bad but getting hit sucks. if she's going to crouch block you IAD'ing at her just use j.C or use a j.236B which if you're high enough and have two IADs, you can do a mixup
2) meter doesn't really help you put out more combo damage... the only ways i usually hit miyako in the air is early j.A, pre-emptive j.A from above, and well spaced/timed jB. other than that i mainly use ribbons like early j236b, backdash j236a...
3) if miyako is directly above you, bad times. if you're close enough to air throw you should take it, and if you're in position for a j.B, it should idealy come out before her shit comes out
4) learn to use her tools. are you using staggers? are they respecting them? are you using TK ribbons? possibly EX ribbons? mixing in jumps or IAD j.A? do you practice staggers with the CPU set to 'recover A' ? watching match vids would help immensely here...
5) the most reliable way to catch a jumpout after a reverse beat which i'm assuming is a reverse beat whiff cancel with 5A/2A... you have to be immediately be using something to stuff them ie 5C, 2C, maybe even 4C, 22C ignition, or straight up j.A, air throw... basically NOT a re-dash in usually, especially if they are just holding up so they will jump asap. EX 236C post-block frame advantage is distance dependent. the j.B in jAB jc jA mixup is optional... some other mixups you have is just straight up IAD j.A high/low, airdash drop airdash jC... airdash whiff jC low... just watch more match vids really
6) i dont really remember how momiji loop tk j22c tk7 ribbon is... im pretty sure that doesnt even hit meaty actually. if you are talking about momiji xx 2c j7 or j7 j22c falling j236a... thats another story and that is generally meaty and safe
7) i dont actually think c is ever better than f but to be honest ive never really given it too much thought. f has air puff, air pillars... they are pretty awesome tools. c lacks in the damage department, especially midscreen and some of her normals are worse (no gdlk jC, 5C wallslams) and her tools are different.
some food for thought...
getting a pit every time off of momiji is something you may want to rethink, the momiji knockdown is an excellent time to do double airdash mixups, superjump empty low or airdash high mixup and setting up the pit takes away from this... of course you can also airdash at them and jump to bait the reversal... arguably you can wait till you have a pit to get this kind of mixup OR you can learn to set up the EX pit mid-combo by spending an extra 100% meter with EX momiji...
as for pressure, make them respect your options and reset pressure at points where you think they will respect. another tricky way to punish jumpouts is to do something that will entice them to jump out but then force them to airblock something right away and break their guard... ie IABD airdash j.AB or j.C is great for this... there are various options. watch more match vids. they don't even have to be CC match vids.
EDIT:
-Add 5B 2C xx 4C to your Momiji reps. From what I can tell, this is THE most damaging variant.
Is it possible to do this on both the second and the third rep? Every time I try it I drop it on the last rep, 5b is kinda slow.
this is very possible, make sure you tap 5b instead of holding it and delay the 4c. iirc 5b is only like 7f and 4c is around that startup too
EDIT:
~5c4c2c623b 5b2c,4c623c j22c 2a2c,4c5bb623b
best damage i found for xx 623c j22c xx