Refinancing primary residence

[Charlie John]

Hey BP,

Hoping to get some insight into financing... 

I have two mortgages on my primary residence. One is for $320k at 6.0% for 2.5 more years (private money) and the payment is $1950. The second is for $85k at 3.0% (substituted collateral from a flip I did earlier this year and placed the debt to my primary residence) and the payment is $917. At the time, my prior two years tax returns were not good enough to get a traditional loan, so I bought it using creative financing. However, after 2018 and 2019 tax returns, I feel very confident I will be able to qualify for a loan for 400k. I own the house and am on title, my lenders are in first and second lien positions.

Primary residence is worth around $575k. The first mortgage is coming due in the next few years. The second is amortized over 10 years and will be paid in full in 9 years if I keep it in place. 

My question is -- Will lenders allow me to just refinance out the first mortgage of $320k? Or do I need to roll both mortgages into one lump refi?

 I do like the idea of keeping the second mortgage in place (even though it is a high payment) because every payment of $917, my balance is reduced by about $700.

Also-- what kind of fees go along with refinancing this mortgage? Obviously an appraisal and credit check, but what else?

Thanks so much BP! I enjoy getting the opinion of you guys first before approaching a local lender who may be narrow minded.