Default Transferring from S3 to Note 3

I'm going to buy a Note 3 tomorrow and I'd like to transfer my contacts from my S3 to it. Most of my contacts are saved to my Samsung account but I think some are on my Google Account.

Is there a way to make sure they are all saved to one account and then transfer them over by just logging into that account on the Note 3?

Also, are there any must-have accessories for the Note 3 I should know of? I've seen the wireless chargers - do you have to have a special case for these to work, or do some of them work with the phone and a normal leather (or similar) case?

Any help would be appreciated!
Cheers