The MCHN and paediatrician both pointed out to me that the valve at the top of some bubs tummies is not very strong initially - and that it does get stronger. In a few months the vomiting should go away - and as long as weeing, pooing and growing are all happening then things are on track.
Do you have a sling (and are your little ones big enough for you to feel comfy using it)? Keeping uprightish after feeds (maybe even for an hour - bubs will happily sleep in slings) helped us a lot too.
I also dressed my little guy in separate tops and pants so that we could usually just swap one half of his clothes, since he hated being naked, and hence changing him made him sad. With the bottle feeds, stop and wait a few seconds maybe 4 or 5 times during the bottle - don't let her guts the lot. This is partly from a chucking point of view, and partly from a that-is-what-breasts-do-so-keep-it-as-similar-as-you-can point of view.

Congrats on your twins safe arrival too!