Creative Financing for Down Payment

[Kelvin Letron Brantley]

I'm planning on using my current primary residence in Tega Cay, SC as my first rental property.  I want to purchase a new primary residence.  I'm thinking the best way to go about it is:

1.  Get approval for financing on new property.
2.  Move out of current primary residence and lease/rent it.
3.  Start shopping for new property.

Is this a sound strategy?

Also I'm wondering if the bank will only lend 80% of home value, is it legal to negotiate creative financing for the down payment with the seller?

Thanks