Surprisingly the investor component has been the easiest part and I have $5mm ready to deploy for this if needed between a few different investors who are super stoked to get into the better neighborhoods in the area at an 8% cap rate. 

The downside to HOA properties is you always have a business partner who can dramatically affect you yet who's interests aren't really aligned with yours.

The sponsor rarely has much skin in the game, and thus their interests may not align with yours (e.g. you may want to protect capital, but they don't get paid until they exceed the preferred, so they may take extra risks to try to outperform).

most cities of your size have some long term established HML who allow folks to invest in their deals.To me the foreclosure rules are a key component .. when your buying notes that you did not originate.

I guess I just need to find someone aligned with my goals.

Yes, look around for one that aligns with your goals. 

You can take participant loans from the plan, you don't need the additional expense and administration of an LLC to have checkbook control, and there is a built in-Roth component.

Truly self-directed Solo 401k is an excellent investment vehicle which can be used to build wealth quickly, but understanding and following the rules is a crucial component to be successful with it.

Having that alignment can really help cut down on friction. 

There have been many I have chosen not to align myself with.