Just turned 60, and am usually giving guns to my (all grown up now) kids as presents. That has the added benefit of justifying that I still make occasional purchases.
Bedside gun: S&W Model 15, 4 inch, loaded with 125 grain +P.
Gun in my pocket while I'm outside working on my farm, S&W Model 66, 2 1/2 inch with 1 148 wadcutter (for little stuff) and 5 158 grain .357 Magnum rounds (we have bears).
Walking in the woods, S&W Model 1066 loaded with Underwood 200...
Hmm, tough decision. If it were me, I would fixture a piece of stainless rod of the proper diameter through the safety hole, and MIG enough aluminum in to be able to machine it back to fit the safety. Lacking that, there are industrial adhesives even better than the choices you mentioned.
If her hands are too weakened from MS to rack a slide, I would guess that recoil is also an issue. A Ruger LCR in .327 Federal can handle all the lighter recoiling versions of .32 ammunition: .32H&R, .32 Long, .32 Short, or even .32ACP. All are milder recoiling than .327, which already...
I'm not getting rid of any .22LR guns, but I have almost quit using .22LR for small game/pests. I use .22WMR almost exclusively now. However, on the few occasions when I need to use a low power quiet round, I use one of the low report rounds in .22LR (Aguila Colibri, CCI Quiet-22, etc).
I prefer the brown leather myself, but be aware that both colors will stain a light-colored shirt if worn for any length of time.
Being skinny, I found it uncomfortable to wear the regular duty belt with a gun, 2 magazines, cuffs, light, and a baton. Too much weight to stay in place, and...