So even if you pick a state with stronger protections like WY or NV, the cause of action arose in the state where the tenant fell, so likely that the court where the accident happened would have jurisdiction.California tends to have more laws on the books and requirements and restrictions that it can be a good idea to form a CA LLC for out of state property so that you as a CA resident are covered, and to try to have your contracts fall under the purview of CA courts.

Some have restrictions on allowing investors to purchase.

There could be HOA restrictions in addition to COH. 

But with covid restrictions most banks have moved away from the Heloc.

COVID restrictions offer protections too that can go beyond what the PTFA offers.But most foreclosures are of owner occupants, and those people are not removed by eviction actions; instead, an ejectment must be performed.

I'd definitely recommend talking to some smart architects like @Samuel Pavlovcik and @Prashanth Mahakali, they will be able to you with all the restrictions

The Dodd-Frank act passed after the great recession puts a lot of restrictions on what you can do. if you want to do this I highly suggest you read Lonnie Scruggs' book Deals On Wheels (which is a great presentation of the idea, but technically now illegal), as well as the supplement that Lonnie Scruggs and his attorney published a few years ago that specifically addresses seller financing mobile homes in relation to the Dodd-Frank act.

No restrictions on tax, but once a kid starts making certain amount of money, they will be subject to other code sections. 

Unless you have enough street parking, the HOA may have restrictions on how many cars per unit.2-  I like to BRRR my properties.

The covenants are non-restrictive (we border the city, but are not in city limits.