Setting up a new mac -- with a new AppleID -- but old iPhone has old ID

[Ken Sp.]

You can export your contacts on your Mac or even from iCloud.com then import them where you choose.
In iCloud contacts-use the gear in the lower left.
You can share iTunes AppleIDs and have your own iCloud AppleID. This fall you will be able to do "Family Share" with multiple iTunes AppleIDs.

PM me---I set this stuff up all the time---Happy to help.