So if the business that adopts the plan is the GC for that house and uses the money from the solo k  is that a prohibited transaction or would I need to hire a different GC to use that money?

My landlord policy prohibits day cares.Whenever people ask about day care, my answer is no, even when they offer me offer extra money.

Conducting business with disqualified persons will result in a prohibited transaction and will disqualify your IRA resulting in severe penalties.

Here's what it says on the IRS's website involving disqualified persons:Prohibited transactions in a qualified planProhibited transactions generally include the following transactions: A disqualified person’s transfer of plan income or assets to, or use of them by or for his or her benefit A fiduciary’s act by which he or she deals with plan income or assets in his or her own interest A fiduciary’s receipt of consideration for his or her own account in a transaction that involves plan income or assets from any party dealing with the plan Any of the following acts between the plan and a disqualified person: Selling, exchanging, or leasing property Lending money or extending credit Furnishing goods, services or facilitiesExempt transactionsThe law exempts some transactions from being prohibited transactions.

'prohibited transactions' that don't impact LLCs.

That made it cost prohibitive to open up entirely. 

Arizona's laws that prohibit deficiencies are found in Arizona Revised Statutes Sections 33-814.G and 33-729.A.

Be very careful with that, Federal law prohibits discrimination against that, the only time you can specify a certain gender is if you live there, or if say your son or daughter lives there, then by law you can specify a Gender - check out Fair Housing Act: https://www.justice.gov/crt/fair-housing-act-2

I think they prohibit them here in Dallas.

It is like saying the solution to alcoholism is prohibition.