I’ve had recipient holders pass away and our HAs always passed their voucher to someone else in the household.

Are you from the US or are you here on visa?

Here is the post you referenced in tenantsunion:Section 8 Voucher Discrimination Your Housing Rights and Section 8 ProgramsIn the City of Seattle, unincorporated King County, Bellevue, and Redmond it is illegal for landlords to discriminate against someone because of their status as a Section 8 voucher holder.

Can the title holder claim the mobile homes or their rights were taking away once the property converted into a real property?

That is, if a real estate loan is originated by either license holder, there is no limit on the interest rate that can be charged.

He's been around the proverbial block vis a vis Buffalo housing idiosyncrasies....

Vega SanchezIn a very broad definition :Purchasing the debt of a single family home or commercial property which allows you as the lien holder the right to collect the monthly payments. 

If you advance money to him, make sure you are on the title as a deed holder. 

-Do your parents want to be equity holders in this new venture, or loan you the money? 

If they can afford it and if you want to continue to be a note holder on this property then it is a valid strategy.