Yeah, I had the same thought re: re-doing the medicals, hope not... I have 3 children who live in the US and are not going to live with me in Canada. Getting my EX to take the kids to get medicals re-done will be a fun challenge.
I'm not sure why the background checks took so long. I am a US citizen (living in Canada for 2 years on Visitors Records) and have only lived in the US (2 states), no military or political service. No criminal record or arrests, the only things I can think that may hold up my background checks is (1) my first and last names are very common for the western states. (2) I had an ongoing divorce for the past 4 years, recently finalized.
I submitted complete police certificates, FBI to Buffalo in FEB 2010.
Since the kids are non-accompanying, it's doubtful they will have to re-do them. The common name might have produced a hit on some security list somewhere that caused the delay with the background checks I suppose. Hard to say. But hopefully you are almost done now.