I got my new iphone. If I activate it, what happens to data on old one?

If you transfer the number to the new phone the old one will no longer work as a phone except for 911.

The other features on the phone like wifi and apps that do not use a cellular connection will still work.

Basically becomes an iPod touch.

Yes, you can sync both. Just check the apps and music and other otems you want on each device.

Yes.