Work with your commercial lender/insurer/lawyer/personal banker and see if they know of any interested parties.4. 

Florida is a unique state for MHP law and the insurance has gotten very expensive there too.I recommend checking out @Frank Rolfe's mobile home university content if you haven't already.

Several options you can explore to get the down payment capital: Solo401k; HELOC on personal residence or from equity of the SFR; Cash Value Life Insurance Policy; Business Credit; Private Lenders, to name a few.

I'm unsure if I would use property management at this point, and there would be some insurance.  

This is a conventional loan where they also cover your PMI (private mortgage insurance).

That helps some...but your variable expenses also go up too - property insurance & taxes - so a lot of your rent increases go to offset rising variable expenses.I started at the age of 47 in 2018 and we bought properties fast and furious - 12 the first year, 10 the next, and 9 in 2021 and currently have 38 properties. 

I have also filed a claim against his insurance company with hope of getting at least our monies from the contract back.    

One downside of MF can be the age, and insurance can be a big issue.

Insurance companies are taking a close look at building materials, quality, and updates. 

And given #3 above, it leaves about 20% of rent for all other expenses like property tax, insurance and other PM expenses like leasing fee, eviction fee and other minor expenses like for e.g landscaping, pest control etc.