They definitely do have sensitive respiratory systems, so non-stick pans, scented candles, incense, strong perfumes, are a no-no.

Green singing finches are a FABULOUS bird, but out of most people's price ranges. I personally love roller canaries as far as singing birds go. Many canaries and finches can cohabit too.

When you go on vacation I would have someone check them every day, if for no other reason than they tend to get their food into their water which can cause bacteria to build up very quickly.

I think as long as they were in a relatively draft-free area, perhaps with a nest-box to escape when they needed to, they'd be all right as far as drafts.

Small birds don't usually require a lot of veterinary care.

Good luck with whatever you choose!