500GB Macbook Time Machine Question I have the new Macbook 12 inch with 500GB, which half of the storage goes to the Windows 10 system. I wonder would 500GB Hard drive be enough for Time Machine for backup? 

Also, I'm thinking of the Seagate Wireless Plus hard drive for it. Will wireless hard drives work just fine?
Waiting!! :)
Yes. You could even get by if you had 500 GB of data to back up. 

If you don't use Bootcamp, tell time machine to exclude the VM hard drives. 

Wireless is fine - the initial backup could take longer and restores will take longer than a USB drive, but you'll get more backups if you don't need to remember to connect a USB.