Because you are smart - your concerns are very legitimate. 

He seem legitimate etc.

If they're grumpy and throwing a fit, they may have a legitimate physiological need for a nap (and it is ridiculous to have developmentally inappropriate expectations of their self-control--I get cranky when I'm tired, too, even now!

Legitimate videos would be fine too, it's just that I don't trust most of the videos on Youtube because the creators of those videos have something to gain through promising that their videos will immediately land deals (guru nonsense).Thank you

Should also add- if tenant has resisted there for one year or longer and reason is not provided on request to vacate, the notice to vacate is voided and not legitimate

It can also turn into legitimate deductible expenses for you and bonus if  you open a Roth for them as well!

Are the above approaches legitimate even thought they essentially imply that I got the house for "free" given the price of land in the area.

Luckily I was able to legitimately disqualify them because of that.

I have seen plenty of videos talking about it but of course have no idea if these are legitimate methods as I have never rehabbed a house and therefore have no clue if these values are anywhere near correct.

If you're legitimately trying to buy an investment property their shouldn't be an issue with you living in an apartment.