So I specialize in creative financing types of deals (Lease/Option, Sub2, Contract for Deed/Land Sale Contract etc...).

A contract (lease) is only as good as the people that sign it. 

Start setting up appointments and put houses under contract (this can be a simple one page contract that shows who's buying, who's selling, the address, the amount, any other terms, and signatures.

And if you get any pushback, I'd contract an attorney. 

I understand that HUD doesn't allow "and or assigns" to the contract, but I can add a buyer. 

Alternatively, you can put your agent's name on the contract, and do the acquisition work yourself.I highly recommend not making offers without seeing the property first. 

Aside from learning as much as I can through books, online forums, and the BP podcasts, should I look for a local investor that flips homes and offer my contracting services?

I would write a contract or have an agent write a contract to them. 

Is it possible to propose a seller financing option to a buyer with a property you have under contract from a wholesale deal?

They only thing I have contracted out was putting in a 18' steel beam.