There are companies out there that will finance you for only 10% down. However, the interest rate may be slightly higher. This is because the "no MI" ability has you finance the MI through the rate. Basically saying that the bump in rate is paying for the MI (also called lender paid MI). A fixed rate in this scenario may be much higher than other alternatives. Since we know values are going up, ask Mr. Peters to offer you an adjustable rate of 5 or 7 years. This will get you a much lower payment which after such time, you can refinance into a fixed rate deal.
Ask him if he offers a mortgage split of 417k/168k. You'll still only have to pay 10% down and you still won't have MI, but you will have a second mortgage at a much higher rate. The great part about this however is that the first mortgage can be fixed for 30 years at a conforming rate instead of a non-conforming rate. The second mortgage comes from a credit union or small community bank.
I would then recommend taking the other half of your savings and put it towards the other house and pay down the pay off. Get rid of that debt so that you can live more stress free.
Have someone assume your current mortgage (depending on the type of loan that you have) and ask the loan officer if an assumed loan means a sold loan in the eyes of the underwriter. If it does mean the property has been sold, then your reserve requirement will be less. Then follow the other steps above.
You may also want to look at homes that come from the FDIC and haven't hit the market yet. Sometimes you can find properties at 40 or 50 cents on the dollar, especially when talking about jumbo priced homes.