options for first time buyer with student debt
There are a couple other factors, however, depending on local lenders there might be some "Doctor" programs that you could take advantage of that allow/understand the student debt loan of a recent medical school graduate. There are additional factors with your current work position, credit...

can i refinance to remove myself from the mortgage?
Yes, its simple if your spouse would qualify for the mortgage on her own, then you can be removed from both mortgage and title if you would like. Its all up to if she can qualify.

best way to go from fha loan to conventional
Yes, conventional refinance woudl be the best way and even if you dont have 20% equity there might be some options for you to either go with a Lender Paid MI (LMPI option to not have to pay it. However, with a decent credit score and good loan to value the conventional MI costs are considerably less than...

if i locked in my rate is it too late to change it?
Depends on how your loan was setup with your loan officer and the only other options would be to possibly look at competitive quotes and pricing to make sure that you are getting the best deal possible.

is mortgage insurance thru FHA dependent upon credit score?
FHA has fixed Upfront Mortgage Insurance costs (1.75%) and monthly (1.35%), however, we are hearing that there might be a change to the FHA costs here soon. If your credit is at 687 there are some conventional loan programs that allow for only 3% down payment that would possibly be a better option for you.

Does VA offer any sort of HELOC/home equity line?
No HELOC options through VA but a cash out refinance up to 100% or if you have equity in the home there are lenders who provide HELOCs up to 90% or 90% total loan to value if you are looking for the flexibilty of that type of product.

3% down payment loan.
There are a few different loan options that you have through FHA with possible grants as well as conventional 3% downpayment programs as well. Military/VA loans allow for 100% financing but you can quailify for 3% down payment programs if you havent served.

I am underwater on my mortgage and want to use HARP, can I with 660 mid credit?
Yes, as long as you meet all other requirements your credit score should allow for you to refinancing through the HARP program.