I agree with EricEng.
I'd look into the WHY of the assessment. If they ran short of ca$h and needed an assessment once, there's no guarantee you won't get hit with another one. I'd check their Reserve Study documents very carefully. In fact, I'd pay a CPA to review all the financials before closing. Absolutely worth the money.
Speaking completely under the cloak of anonymity, I'd think long and hard before declaring the income from a roommate. You're going to open up a can of worms. You'll need to take depreciation, and pay it back when you sell. "Oh, you didn't take it?", the IRS inquires politely? "Too bad, we can still tax you as if you did." And they will.
From a mustachian POV, if you *need* a roommate to afford this place, you can't afford it.
Oh, and one more tip. Run those HOA dues through an inflation calculator so you're not shocked at what they become over five, ten or more years.