Double sided is fine. We send them all double sided and never had any problems.
You can e-file from outside the US - this is the first year you can do so.
Just to point out, that if you have children, depending on your income, it may well be better not to file the 2555, in order to get Child Tax Credits. Every situation is different, but someone with a couple of kids and an income of $30000 would get a few thousand dollars refunded, but by using the 2555 they won't.