-Have they asked for an in-person interview? I mean, I'd just respond that you're out of the country for work (if that's true of course) and your return date; offer to provide more info if needed. It can't hurt to state you'd be available for on-line interview.
-I don't know. As far as I'm aware, if you've filed taxes for previous three years there should not be an issue but again - do not know.
Side point: for spouse's app, we got the request for passport copies (all pages with stamps), it was a strong clue that it was about physical presence ('clue' in sense that I was 100% certain but my spouse worried anyway). Obviously won't apply to all cases, and I wouldn't want to guess.
I can say that most of the cases I've seen reported here where people had interviews, they went quickly (I'm pretty sure they don't have more than 10 mins scheduled for it) and didn't end up being a big deal. Now this may be selection issue, i.e. those who have more serious issues come up aren't reporting details here, although just by math likely problem cases are relatively uncommon.