I'm soon to hit the 2 yr mark with my family plan, and will be getting
a (single) new phone. When I get the new phone, I'd like to swap it for
a current phone and, seperately, swap the phone numbers with the other
handset as well.

For example, this is the current setup:
Handset A & Phone Number 1 [Current phone]
Handset B & Phone Number 2 [Current phone]
Handset C [NE2 new phone]

Will become:
Handset C & Phone Number 1
Handset A & Phone Number 2

Can I do this online via the ESN activation section of the VZW site?
Any hints to making this work with fewer hiccups?

Is the NE2 deal the same between the www site, phone or store?

thanks
Matt