I would let the lease sleeping dog lie.....right now it appears they have no binding lease, so you have flexibility to put them on month or make them sign Your lease.

My landlord is beyond motivated to sell me the condo and is interested in a cash transaction with much flexibility.

Good choice.Most tenants will be pretty flexible when they find out they are getting a brand new floor.

I find commercial appraisers are much more flexible than residential, and love you to do the work for them. 

As i have no ties to any local area, i would be flexible in my area of investment, so where would you recommend me focusing on?

After selling an investment property, OZ real estate investors roll only their capital gain into an OZ investment, and then have the flexibility to consider other investment options with the remaining proceeds from the sale of their property. 

Each of these variables seem fairly flexible, so we are just trying to make sure our offer is in line with seller-financing norms.

I am flexible to live in any state, but prefer Texas, Colorado, Florida or South Carolina.Looking for analysis and feedback on how to make this deal better!

A smaller bank or credit union is typically more flexible, so I'd try calling several of them if that's what you need. 

This means, if a seller can wait even 3 weeks to get their money I can have a lot more flexibility in my purchase price.