To my knowledge I am not  aware of codes that will legally allow renting a in-law suite.

I personally would rather lose a few bookings here and there, than put myself in any possible legal trouble. 

No legal advice given.    

That's the best way for a ton of legal reasons.

@Thomas S. so we can give advice and we won’t be in any legal issues? 

Or would their be legal repercussions if they do background checks and they find out that they don't want to rent to these people?

That means that he is legally required to work in the seller's best interest, which usually means getting the highest possible price, at the best possible terms and closing on the timeline most beneficial to the seller.As others have pointed out, getting a buyer's agent is at no cost to you. 

Are there any creative but legal ways to use my personal funds and the SDIRA on the same projects?

If I were you, I would contact an estate lawyer, or have the siblings contact one, to legally see what the other 4 siblings options are.

I know its not legal.. but I self insure myself in that regard. some say its recession proof and some say not.. my banker says not.. he says when economy gets tough they just won't spend 200 bucks a month to store their stuff they either up and leave it or move it somewhere else.. so that's two opinions.my units were quite unique one they were A class and two right across the street from 300 floating homes and all my tenants save a very few had house boats.. so I kind of had a captive audicance and once I got it converted to mainly all houses boats..