When I tried to get it when my side of the family found out and tried tp take over reverse mortgage payments to bank because she had died it was to late so they sold the house to Hud and then other reverse mortgage companies but a relative still lives there so they can't kick them out.

They are a corporate housing company.

I called my local insurance company, as well as two major companies and was told "good luck." 

The people that run these companies usually come from an "investment banking", real estate, or construction background.

My current property management company doesn’t offer this service, and the only company I know of is very hard to communicate with.

Sounds like your 2 previous companies didn't know what they were doing.

The ones that build out great companies build the skills, then they teach the skills to people to set calls for them, go to appointments for them and they continue to build out their company as a marketing/sales operation that is more fluid to create more revenue. 

I’ve been contacted by the Angi company but I’ve read a lot of negative comments regarding how the treat their contractors.

I know the larger companies around here were charging up to 25% but it will probably vary no matter where you are at.  

You could also use "Doug's LLC and/or assigns" where Doug's LLC is your hypothetical company.As for the assignment contract, you can get one from an attorney for probably less than $1,000, you can also make a friend at a title company, they probably have a template they could give you.