The 1% rule (and sometimes the 2% rule) was created for evaluating mobile home parks and storage facilities. 

They claimed they needed to let someone go due to a budget restriction, and it may as well be me because I’m moving on anyway and clearly have something to move into.

If I'm reading the rules correctly, under 10,000 square feet, RH lots are limited to 1 unit/2,000 with maximum building coverage of 85%.

Any thoughts on how he could get around these rules? 

Rule no 1 when you purchase a home with the intend to flip.

Because public advertising for investors violates SEC rules and can land you in a world of trouble. 

One of the keys for landlords is that the new rules significantly lower the number of surfaces that have to be deleaded...which lowers the cost of abatement compared to the law pre-12/1/2017. 

Are there any restrictions and risks of renting a SFH for business plus residence purpose?

@Chatree C.You will need to find a Solo 401(k) plan document provider and then you can have the funds reside at the custodian that you mentioned or at a local bank if you prefer.The Solo 401(k) provider will also assist with the ongoing compliance requirements such as filing form 5500-ez when needed, processing plan updates and  also answering technical questions regarding the rules and regulations.Regarding UDFI, this tax generally does not apply to the Solo 401(k) plans.

In the Property Disclosure -> Covenants, Fees and Assesment section, the seller marked YES to Q:Is the property subject to a recorded Declaration of Covenants, Conditions and Restrictions (CC & R"s) or other similar restrictions.No explanation notes were provided.