You have a very nice income. What's your spending like? What is this first property--a rental unit? Why $300k for a primary residence--are you in a HCOL area? What's your time frame for moving into a primary residence?
In general, you want to get rid of high-interest-rate debt first, and minimize your income tax liability. With that in mind, here's my advice (in order):
1) Max out the 401k/403b for both you and your (soon to be) wife. ($36k/year)
2) Max out traditional IRA for both you and your wife ($11k/year)
3) Tackle the car loan--it has far and away the highest interest rate.
4) After that, hit the first property so you can get rid of PMI.
5) Pay back the student loan to family. Sure, it's your lowest interest rate, but IMO it's extremely important to fulfill that obligation when it's a family member on the other end.
With steps 1 & 2, plus standard deduction and 2 exemptions, your taxable income will be about $115k and your income tax will be about $20k. Your take home pay will then be about $95k.
With steps 1&2, you aren't paying off any loans yet. You said that you can live off one income, but that's $90k (assuming you're earning the same as your fiance), which is an enormous sum, especially since it's your take home pay. If you keep your spending to a princely $60k/year, that means that in addition to maxing out both 401(k)s and IRAs, your debt would look like this:
Year 1: pay off car and get first property to <80% LTV to eliminate PMI ($18k paid off mortgage, down to $108k minus normal payments)
Year 2: pay off student loan and have $20k left over to invest or pay down debt
If you're slightly more frugal and keep your spending at $45k, you could knock out PMI, car loan, and student loan in 1 year. After that, it's up to you--mathematically, it makes more sense to invest the leftover income in traditional investments, but it's also nice to be debt free. You'll have to make that judgment call.