It seems like you went out of your way to fix itShe cannot make alterations to the place and invoice you for them.

Have them submit their invoices.

This is why and GC worth a dang uses a Gantt Charting system.

You have proof in the form of invoices from the utility company that they didn’t pay them and you did. 

You can set a smart form up to ask basic questions: do you earn at least $nnnn / month and have paystubs/invoices to support it?

Now playing in the ~A "sandbox", at least for myself, it's all about path of progress because being IN the progress of ~A class, it's just too dang expensive usually.

I would suggest creating a new bank account just for your rental related activities.I would also suggest doing the same for a credit card.I would also suggest having an online storage app such as google drive, apple drive or dropbox to help save your receipts / invoices.

IMHO if you say "I'm buying your house" you dang well better be planning to do exactly that.

If you can verify the funds you used for Y (HUD showing cash-to-close, receipts/invoices from contractors, etc), you may be able to get Y back as "cash-out" if you are at a very healthy LTV. 

The actual rules are quite complex but you get the basic idea.So keep all your receipts and invoices from 2016, but they won't apply until 2017 taxes.