I'm more inclined to come down on the side of keeping it, purely because it's a small fry debt that currently earns you 18.6% net, not including future appreciation.

Less inclined to do this option, as neither of us wants to be landlords4) Should I offer her a fair price for what it's worth, then buy, fix, and flip?

I am inclined to flip only using my own cash, seems safer.  

The only advantage to renewing their lease is "maybe" they would be more inclined to stay for an entire additional year. 

If we were to do a high end flip or something out of the ordinary we would be inclined to higher a designer/arch.

I am of course most inclined to trust my accountant however I’ve researched some and it seems my contractor may be right.

If that's a risk you're willing to take, and you also have the time and inclination to be an active investor, then purchasing it on your own will make a lot of sense. $30K will not go very far at all multifamily, so your only choice will be a single-family home.On the other hand, if the risk is not acceptable, then in exchange for paying a management fee, you can hire a much more experienced professional to handle the investment for you via syndication/crowdfunding.

If people see the owner paying for his/her drinks they’re less inclined to steal theirs.

There’s always going to be an excuse not to get into real estate investing but if you have the slightest inclination of doing it and/or looking at buying your first house I will always recommend looking at small multi-families first.

I feel comfortable with my ability to complete the work as I am mechanically inclined and I have a lot of experienced people around me.