3) Can i upload my contacts to my new BB via my gmail acct like on android?
I always use Google Sync, that takes care of pushing/getting my contacts under my Google account.
4) Do I need to manually kill apps to save batt/memory?
Yes you do, making sure you never press the "hang up" button, instead of the "back" button and making sure nothing is running in the background by pressing the BB menu button for a couple of seconds to see what's running in the background.