Hiya, Matt. Welcome to the forum.
Bit of a change of pace for ya, going from the Kwak to the America. Still, now you can enjoy the scenery rather than worrying about becoming part of it!!
1.Don't worry about it. It's a Triumph so they handle really well but obviously, don't expect sports-bike levels of lean. And if you do push it too far, hey, that's what the hero blobs are for!!!
(You listen to your wife?!!!

)
2. 2 schools of thought on this:
-If you don't use the switch, it may corrode/stop working/etc. when you come to need it.
-If you do use it, it'll wear out.
At the end of the day, it's a switch. Personally, I use the key.
3. Pushing your bike to a garage or phoning wife/mate to come bail you out is a pain in the derriere so don't do it for these reasons alone!! As for damaging the cat, I can't help ya there.
Check out the "September Rally UK" thread in the "Rides..." section and hopefully see you there.
Neill