Very good Credit.What are some alternate option for getting a mortgage for buying rental property?

Unbelievable.

If you think a deal could be done if you just had the right price (perhaps not with this one given your comments on the floor plan), it doesn't hurt to just check back in with them every so often to see if anything has changed.To your comment about how could someone possibly make money, it could be that they actually lose money on the deal, or they have alternate plans including holding long term, redevelop, live in flip, etc. 

The answer is to stop working with non-ideal clients.Are there alternative ways to do or try something?

Alternatively, start rehabbing immediately using OPM(other people's money).

Alternatively make sure the deal at least works as a long term rental.

On your primary residence you can do 5% down, but on a vacation home you will need to do 10% or an alternative loan type (which almost certainly will not lower the down payment requirement).  

The newer systems are unbelievable when it comes to cost savings.

All alternatives welcome, I'm not beholden to my initial strategy.

If you was like me when you started I had to focus on hustling hard and looking for alternative financing strategies.