Will a xfinity internet for my laptop also work with my ipad?

If you have a wireless modem or router giv8ng you Wi-Fi then yes use the same password on your ipad.

Yes, your WiFi will work on multiple devices at the same time.

Yes

As long as you have Wi-Fi

If you have internet. Just put the internet code in the iPad. You can do this in settinga on your iPad. You can also get WiFi where there are hot spots