. - I would consider refinancing before selling since refinance funds are tax free.

Is buying a house cash upfront and then refinance later be a better decision due to this fact?   

We owe 321K and the market value is estimated between 600-700 (we did not need an appraisal for refinance).

That said....Why don't you both rate and term refinance to eliminate the MI/balloon payment and keep both your homes? 

I don’t know how to expend my Portfolio with LLC name to own and refinance housing .

I recently used the equity from this crazy market to refinance out of the VA loan and into an owner-occupied conventional loan with the aim of reusing the VA loan to purchase another multifamily property.Here's where the dilemma begins.It seems like every month that goes by makes it harder and harder to afford some of these properties, so I would like to jump in and hedge against appreciation and inflation, but I am unsure how. 

Plan to refinance within 2 years and utilize the appreciation to help securing capital from our other two STR in the area.

How many years should you seller finance it before refinance?

I recently used the equity from this crazy market to refinance out of the VA loan and into an owner-occupied conventional loan with the aim of reusing the VA loan to purchase another multifamily property.Here's where the dilemma begins.It seems like every month that goes by makes it harder and harder to afford some of these properties, so I would like to jump in and hedge against appreciation and inflation, but I am unsure how.

I recently used the equity from this crazy market to refinance out of the VA loan and into an owner-occupied conventional loan with the aim of reusing the VA loan to purchase another multifamily property.Here's where the dilemma begins.It seems like every month that goes by makes it harder and harder to afford some of these properties, so I would like to jump in and hedge against appreciation and inflation, but I am unsure how.