Can I invest in a self directed Roth IRA or does it have to be traditional?

If this is your first time investing in 5+ MFH, you might be able to get a financing with a tradition DSCR lender as along as its not over 10 units.

They typically do these types of non-traditional house mortgages.

I often see investors pair a traditional LLC with a Series LLC to function in this capacity. 

I have an amazing investor lender that does DSCR, hard money, no money down fix and flip, and traditional loans as well. 

Their seller side commissions are half of what's usually standard in an area (1 - 1.5% vs. the traditional 3%) I know you're asking about FSBO but maybe Redfin could be a good middle ground for you.

People are willing to pay the high interest rate because they expect to pay off the loan quickly.If you own the home outright, you would go to a traditional bank to cash out the equity.

Currently have 20k in a HYSA and another 20k split between Rollover IRA (7k), Roth IRA (10k) , Traditional/Roth 401k (5k).

One owner is a wealthy casino owner who collects land and may consider selling but for way more than its worth.

It’s not a traditional wholesale deal.If I were wholesaling I would remove mobile homes from my search criteria especially in communities.