With only $20k in the bank account, I couldn’t put down 20% for a conventional loan.

Would I be able to do an FHA loan with KW or do they just do conventional? 

Some credit unions have offered loans at 5% conventional or Vacations around 10%.

In addition, you will have a lot of trouble getting a great deal with an loan FHA product so I would recommend speaking to a lender about using a conventional loan product.

Wondering is it safe to refinance current home from VA to conventional, free up VA loan, then use the VA for next home and use the equity to rehab, then repeat.

A conventional loan is 15% down on a single family unit and 25% down on a 2-4 unit property.

For conventional, it depends what you compare it to.

Initially it was something I was helping a buyer purchase and it took their cost of living down to about $800/month using a low down payment conventional loan, subsidized by the income from the garage unit.

I just purchased two duplexes in Lynchburg, VA with conventional mortgages and a HELOC (primary res) for the down payments. 

Meeting with a Realtor, possibly at the same time, can give you an idea as to what your options are on the market.They will be able to lay out your options - FHA, Conventional, renovation loan, etc.Best of luck to you moving forward!