Answer:
If it is secured by a dwelling (manufactured homes built before 6/15/1976 are excluded as dwellings - 1003.2(f) - 3) then the loan is subject to HMDA reporting. Sounds like you have an Other purpose for HMDA and a Purchase purpose for TRID.
Also, the "additional collateral" classification does not exempt the loan from any other regulation that applies to loans secured by a dwelling - flood requirements for example.