Can I partially use iCloud with someone else's Apple ID without syncing contacts to my device?
Sure thing.

Go to the Apple logo in the top left corner > System Preferences > iCloud > Uncheck what you do not need or sign out all together if you want.

I recommend only checking off only what you do not need while keeping Find my Mac on. This way you can still track your MacBook Pro incase it goes missing.

On the other hand, if you choose to sign out from iCloud, your iTunes purchases, FaceTime, etc... will not be removed or affected.

Hope this helps.