Now I'm thinking about converting it into an AirBnb instead to maximize my profits.

Keep your investment near the T lines to maximize possible tenant base. - What is the customer avatar (for a lack of better words) of a MFH tenant?

I've sold multifamily to a lot of owner occupied clients and everyone goes about a different way based on their comfort level.   

I know a lot of realtors in the area but none that are so fantastic I would feel comfortable recommending.

If you aren't comfortable estimating costs on your own or aren't willing to put in the work to learn how to estimate rehab costs then you need to team-up, partner, or hire someone you like a GC as others have mentioned to help you with this process.

This "re-training" has been addressed above as well but giving them the perceived control of depositing at an institution always seems to make them comfortable.

The best option for a buyer/seller rent back is the PITI of the new buyer, however, if the seller does not agree to that I would suggest whatever you both agree to that you are comfortable with while they stay there and also have a security deposit held in escrow including the rent.

At the end of the day you know your risk profile better than us, so pick an option you're most comfortable with trying (that won't end up in bankruptcy if it goes south) and as the saying goes, just do it.

Your attorney and CPA will likely work close together to help structure everything you need to maximize your goals for your company while protecting you and reducing taxes.

If you are not comfortable signing my new lease, then I will have my attorney draft a non-renewal letter with 30 days to vacate.