Re: #1, will it track GPS satellites without an external antenna? I think the only honest answer is, "Your mileage may vary." You'll just have to try it out and see.
I and many other users (the vast majority I would suspect, based on the relatively small number of problems posted here) have never had any issue whatsoever with the GPS tracking. I routinely use my iFly in my living room and study during pre-flight planning, and I've also used it in many hotel rooms and friends' and relatives' houses, and even indoors my unit typically retains a very solid lock. In my plane, I've never had a hint of a problem.
That said, some people have reported some problems (usually intermittent, not constant). Whether that's because they got a bum unit, or something in their plane interferes with GPS reception, or some other reason, I dunno.