For that reason, we may explore investing elsewhere where we have connections - Tucson AZ and FL - hoping for better potential.

It will need to meet all fire and safety codes per your local building codes.Done properly a secondary unit in a SFH is the best method to generate positive cash flow on a otherwise underperforming asset..  

If so, I would very strongly consider the merit of taking on $300k in debt in order to achieve this level of earning potential and perhaps explore cheaper ways of attaining this education.Rather than thinking about how you can mitigate a poor financial decision through real estate, I respectfully suggest that perhaps it's better to not make the poor financial decision in the first place.  

Additionally, if investing is something they are interested in, it is likely not going to be in note investing or real estate because their likely method of investment is retirement/401k.So, on one occasion, before I even considered seller financing as a viable option, I researched to see who the seller was via public records and whether they owned multiple properties.

You might also want to explore rent default insurance to help mitigate your lost rental income and eviction costs should you find yourself in a similar situation. 

These are pretty steep for anyone and that's why Bigger Pockets talks about the BRRRR method. 

I still have plenty more to explore, but am I just going to be treading water if I keep looking for contractors through online sources (yelp, homeadvisor) that won't blow my budget?

I think my prolongued exploration of it shows I do not want to do anything against rules or I would just do it and not care.   

If you find a better method, definitely let me know.

I will definitely continue exploring the website for more information.Thank you so much.