Biggest issue is that for our standards, the place is a mess.

Yes it will help as an investor, But getting a license comes with its down sides.

The biggest mistake new investors make is in maintaining there rent under market to attempt to hold tenants.

I've had success in negotiating both owner financing and rent to own residential deals in my most recent search, although I opted to back away from those deals because I wanted to just do an all cash transaction on a third/separate deal.I think the biggest obstacle is going through the process when you don't know what you are doing.

I know this isn't quite applicable for you yet, but you can also speak to your CPA (the biggest impact route I've taken) about how to increase your reported taxable income. 

4) What are the downsides of such a lease for the landlord?

The biggest mistake I believe people make is that they just say oh well I can't start now guess I'll wait until the market crashes, or wait 3 years to start.

Or should I invest in my own future and avoid risking my fathers biggest investment.

Biggest question you can’t put a price on, what would selling alleviate stress wise? 

My biggest struggle is always feeling I haven't accomplished anything.