Please see the attached.
I don't really see any requirement about the HUD code in regards leasing a property. However, as you get closer to the time or purchase there may be some kind of requirement. My advice is to contact your local HUD office to get all the details.
Best of Luck,
Manuel Brown, Broker
As for the lease to own, that would be a contract between you and the builder/owner, the end loan will be the challenge, if you can find a local municipality that will allow the structure.