Hey Jo,
I did not catch if there was property management expense in there... Important to pay yourself.
Your vacancy seems high (I use AEDC's number - currently 3.2%), and you can expect about a 100 / month improvement if you upgrade the boiler. On the plus side, you don't need to account for 1 unit of vacancy if you occupy one unit.
I think if you are going to evaluate price too, square footage is a good measure for how much you should pay and how much each unit should rent for. A 1200 sf 3-2 without a garage can rent for less than a 1400 sf 2-2 with a garage. The info in your spreadsheet doesn't include this, but it's essential to analyzing the deal.
As far as the PMI goes - you have to go in with a strategy to refinance. I've read fha PMI stays for the life of the loan, but haven't checked up on the rules recently. So, with that in mind, your plan would be to buy, watch the market and hope it goes up. Traditional loans (non fha) would be able able to drop PMI at 80% ltv. So, then you'd have your downside case at least be known. I'm a fan of using a 5-1 Arm for the buy-refi out of PMI strategy.
What is your strategy for raising the rents? All at once, $100 per year? Just be prepared for the time it would take to re-rent or raise to market.