Is it pretty accurate?

It also seems like a huge risk and gamble to invest in a property without doing an inspection, but it may pay off big.

At best they'd say, "that's not investing, that's gambling."

Property Tax) is accounted for accurately, or is this something I should be verifying and plugging in manually?

He wanted to list at 159,900 and I thought 139,900 was a more accurate price.

I've read some articles on this, and it appears to be accurate.

It’s not going to be perfect, and would just go off general averages, however, ai highly doubt those averages are refined enough to get down to niches, such as a home on the lake vs a home four or five blocks away will likely have vastly differeing occupancy rates.I use its general averages as an indicator of whether or not I want to even bother with an area, if I decide to I then go in and find direct comparable homes and gather data from those ones specifically to create a much more accurate projection. 

That is not 100% accurate also because it is often done by a third party company who does 'drive-bys' to evaluate properties.

@Guy PrimoFor an accurate account of the 1% rule that includes a HOA expense you need to add the monthly HOA directly to the calculated 1% rent.

If that's all accurate, I'd agree that you're entitled to keep her security deposit to cover unpaid rent for the 30 day period she was required to provide notice, OR until you find a new tenant and that tenant begins paying rent.