Hi and welcome.
In order of priority IMO your questions
1) Battery, no one knows how long it/they will last, depends on your driving style, battery age, individual manufacturing variations, temperature etc etc.
It's not the end of the world if it does fail anyway, have a read of some of the threads on here about batteries, it can be replaced, repaired and or re-balanced if reqd.
2) Sat nat sorry I've no idea on that.
3) Honda Access thingy, sorry no idea again.
Try searching the forum for your answers someone may have already asked the same questions.