A portfolio loan is a different loan type that is governed by the bank and not subject to conventional lending rules.  

I'm, by far, not a subject matter expert on FHA, but that is my opinion.  

Approval authorities are under regular review and are subject to adjustment.

I'm not a big fan of communal living personally, but to each their own.Regardless, get someone you trust and with experience to check over your numbers before you submit the offer and be sure to have good "subject to" clauses in your offer in case they accept it and you need to back out later.

We didn’t think we had to – and it nearly cost us the relationship.Moving forward, the best advice I got on this subject came from my buddy Mike Tarpey and again from my main teacher Bill Cook.Bill put like this: anytime you enter into a business relationship with a friend, you should draw up your agreements as if you don’t know each other.

Through experience, I learned the ins and outs of working with contractors and even wrote a book on the subject.

On the financing end we've been subject to FHA's self sufficiency rule for as far as time spanned but recently in early 2016 they (HUD/FHA) changed their 100% income SS rule to be more realistic and added a 25% discount for repairs and maintenance + vacancy.

IMO, the subject of rents is not why we call the current and one previous landlords,  we call to determine (1) did they serve notice of intent to move and (2) would you rent to them again. 

The subject or self-directed IRA is a frequent discussion here on the forum so I would suggest you simply search related keywords and start reading previous discussions, there is enough content to keep you busy for days :-).

This is a subject that is close to my heart!