@Tim ODonoghue congrats on your first investment! Some things I would think about based on what you said:
1. Do you have to sell your current property? If it's cash-flowing well and doesnt require too much monthly maintenance, can you leverage a HELOC. Just a thought, why not keep a cash flowing property if it still makes financial sense.
2. Based on your downpayment amount, it sounds like you are going to be doing some low downpayment owner occupant loan, like an FHA. On those mortgages, you are technically saying that you'll be living in one of the units (though of course this is a gray line and I know plenty of people that just go ahead and rent all units --everyone has their own risk appetite).
3. In terms of a rental, going back to the second point, why wouldn't you just move into one of the units in the 2 family that you buy? If you go rent another apartment, then from a pure financial perspective if your rent is higher than the rent collected from the second unit, you'd technically be losing money.
Just my 2 cents on this. Also, as a heads up 550-600K for a two fam today around the Everett area is going to buy you a pretty dated and small 2 fam. Make sure you account for potential upfront work you'll need to do and make sure you are pulling proper rental comps. As @Avery Heilbron said in his post, 2 bed/1 bath units are doubtful to get 2000 in rent. I've got a 2 bed in decent shape that I'm getting 1650 for (prob 50-100 below market, but still). Good luck!