Have them send you a line by line item of what's needed.

I'm wondering how much specifics I need to include for each line item. 

Here is a critical item I ran into with other properties: Avantstay has a vendor to take out and bring in the bins.

This is true for bonus depreciation items as well.  

The other business I run is reselling, listing items on eBay & FB.

What were the biggest line items?

We have 8 business entities availing of their services, and as "advisors", they should make business life easier -- not add more work on your plate --- but instead, my team and I have been checking for mistakes, or following up on action items, missed deadlines, and paying penalties to the IRS and Secretaries of State due to their negligence.

The property taxes will be on his Schedule A during the time the property was his primary residence, assuming he itemizes.

It is not your responsibility to house this person's items indefinitely in your rental. 

Gifting equity in a house may be more trouble than it is worth if you are not near the life-time exclusion1) Potentially having to get the property appraised everytime an equity is gifted2) Having a title company update the title every time3) Exemption of the gift tax return is normally for cash gifts below the annual gift tax exclusion, you may still need to file if you gift non-cash4) If there is partial ownership over several years, having to properly pro-rate certain items such as real estate taxes, mortgage interest and rental income if the property is a rentalBest of luck