Will definitely keep this all in mind as I move forward.

If I was the originator on this loan (loan officer, lender, or whatever title is used), I would have made this restriction very clear to my borrower if they had explained that they wanted to eventually use the property as a rental.

If so, any recommendations on brokers that would be willing to partner on something like this? 

Am I being dumb by NOT waiting, because it’s unlikely - I assume - my next deal will be as profitable (I got very lucky on this one!)

This can lead to "renegotiation" demands at the closing:(Other Potential Issues to Consider:Being in the chain of title is also exposure to potential legal issues.Selling an assignment may be a violation of a state's real estate statutes.Wholesaling w/o a real estate broker's license may violate your state's statutes.I'm sure there are more...

I generally rule out most single family homes as viable rentals, as prices are pretty high relative to rents, so aside from some downtown neighborhoods, typically you do not find large areas of single family rental neighborhoods (a median sale price on a 3 bed, 2 bath home so far this year in Dane County on MLS sales data is at $430k). 

@Matthew Kwan, he is asking why the underwriters will not allow him to use the proposed rental income from the subject property at time of purchase.

For anyone who has experience with this, 1) is this a good route to take?

If you can provide this, please do so.

You can't use these apps for international transactions.