Wow - how old are you? Wish I had your planning skills when I had student loans...
So, here's my "slow down" advice, which isn't what you've asked for, but I'm a crotchety middle-aged lady with experience both as a live-in landlord in Portland, and now as mutli-unit owner who hires out the property management.
My advice is to not get there quicker, but spend the next year learning. See how this first property goes. You'll learn about the unanticipated expenses, the joys (?) of landlording, dealing with surprise repairs, and finding good contractors (especially in Portland area, can be tough to find the ones who will do small jobs).
The fact that the property is running -750 currently seems to be a pretty narrow margin of potential profit when you move out -- though I obviously don't know how you've calculated expenses, and don't know how much you can increase rent with improvements. Have you factored in property management when you leave? It can take a lot more time wen you don't live in the building to manage the property. Trust me - it can be as much work as a part-time job.
All kinds of things can happen over the next few years. Planning is great, but over-planning can shut down the flexibility you might need as you learn more about your building managing property, your skills in dealing with people, subcontracting, and finances, and learn what you and your partner like to do and what you hate. This will all inform your next steps.
Who knows - you may want to sell property #1 and use profits toward a higher end, or another type of income property in the end. Or you may really like the building and not mind living with your tenants and live for free. This is all stuff you'll learn.
As far as paying down your debt, I think paying off your largest/highest rate loan makes sense. You may want to accumulate cash so that you can be more flexible with plans. You can put the cash towards your next property, and/or unanticipated expenses with your current property, and/or changes in the economic climate. If you accumulate cash and decide against purchasing another property, or accumulate enough equity in your current one to draw out funds so you don't need the cash, you can always use it to pay off your debt - if that seems to be the right thing to do.
Enjoy the ride!