What material/style are your gloves? As far as altering them, it sounds like it might depend on how long or short you want them. If you like the current length, you should probably have the seam taken in and shorten the elastic. If you think they're too long, shorten them, but you may still need to take the seam in a little to make sure they're not baggy. But if you shorten, you may just have to refit them depending on how stretchy the material is.

As far as the top goes, I'm not sure if silk alone is going to be strong enough to support a hook and eye bra-style closure. It sounds like you might have to add another torso strap altogether. And depending on how much silk you have, cover the strap with the silk ribbon so it matches the rest of the bra. Usually when I make bra straps to go around my torso, I use layers of grosgrain ribbon and interfacing, which is very durable and can take a lot stress that I don't think a silk ribbon alone could hold. I just see it ripping and fraying under stress around the hooks. But other more experienced seamstresses may think otherwise.