Play PUBG on Remix OS

You have a Pandigital Novel. I.e., it's a low-end device that can't run a game like MC2 and is not supported. They only support high-end Samsung, Motorola, HTC and Sony devices. From their FAQ:

My phone isn't listed; can I order the game for a different phone and use it on mine?

If your phone doesn't appear on Gameloft's site, it is not supported. Picking an alternate phone, even if the model numbers are similar, will not work. Before adding a phone, we perform various tests to make sure that we can maintain the quality that gamers expect from Gameloft. However, we regularly add new phones to our website. If your phone isn't listed on the site, please check back regularly. If it's a popular phone, it's likely we will add it as soon as we can.

Get a refund if you can.

As I understand it, if you authorize Google Play for her phone and you're OK with her using your account and having access to all of you downloads and payment method, then there shouldn't be an issue. If a piece of content has an activation limit, it will typically tell you. For instance I have purchased a backup application but it can only be active and installed on one device at a time. For the most part I believe Google leaves the limit selection up to the individual developer.

But, Google did recently implement a 10 device limit as you can read here:

http://support.google.com/googleplay/bin/answer.py?hl=en&answer=1230356&topic=2450456&ctx=topic

You'll see tighter limits more active in the music and video areas as you can see here videos have a 5 device install limit, but can only be played by one device at a time:

http://support.google.com/googleplay/bin/answer.py?hl=en&answer=2666462