It is all or nothing as there is no selective restore. If you were especially going to tether to iTunes you would do a full backup on your current phone, Tether your new phone and when you get to the point of how to set it up, I would then restore from a previous backup. When you do this it is not broken down for you to choose what to back up and it is going to restore what you backed up and that is everything.
I asked the advice of a good friend on here that does this to his own phone quite often and does frequent backups to iTunes and iCloud.
As he told me, I would initially do the restore from a previous backup and then several days later he sets his phone up as new. having said that I would do all that and watch the phone for the several days. If everything stays well I would leave it alone after that and that is what I am going to try. Good luck, i hope this helps and works out for you. This IMO are what most would do and tell you that is what they do, After all we are all lazy to a point when it comes to this kind of thing.