Rolling opamp tunes the sound to a degree, can get you a small performance boost if you use something like LME49860 or OPA827, but from what I read, slight changes won't be enough for M-Stage to compare to the H10. You're better off going with the H10.
I intend to as well, later.
If a pin falls out completely, superglue it back in and reconnect the voice coil lead(s). Only one lead per pin. Search for the leads beforehand, make sure that you can find them first, if not, you can write off that driver as effectively dead. A 10-15x magnifying loupe plus plenty of light can help.
The pins are just to facilitate connecting the cable's wires to the voice coil leads.
If you actually lose a segment of lead (or both) but can still reach them, tin...
Judging from photos, HM5s should fit. They will stretch a bit to do so, it may be troublesome the first time you put them on. I doubt that they will need to be stretched as much as is necessary for DT770 or K553.So 99.99999% confidence of them fitting that Noontec, haha.
I tried DT880pro, DT880-600, DT440, DT1350, and own a DT770pro-250, T50p, and T90. Burn-in is subtle, just a bit more clarity and tightness to the sound. You can safely write it off as not worth any attention.Burn-in has been more noticeable on Audio-technicas and film capacitors I've tried.