He has a W-2 job.

Understand your comps, a agent will get you the data but it is your job as an investor to really know what you can sell it for.

Below is more context:- We all have full time jobs and in our early 30's- 2 of us live in New York City and 1 lives in Boston, if that matters- All of us are planning to do equal investment and buy the property in all cash- Our strategy for the first property is to go for cash flow - We are only going to buy one property under this LLC. 

if something like robbery or vandalism happens to the house while it is vacant, who’s liable for the loss ?

Honestly it is a pretty thankless job with tight margins which is why it is hard to find good ones.

I‘m still making decent cashflow from my job, but I’m considering buying a condo/townhouse for myself first to lower my monthly living expenses (I could move just outside the city for ~$600 less per month).

I am looking for a job or internship of some sort and don't really know what positions are out there that will help me learn.

No just to let you know my end goal is probably only 10 properties enough to live off of and quit my day job.

This is also likely to be at a time when the economy is poor and your own day job may be in peril.

I've been reading as much as possible about REI and decided I wanted to go with a long term rental strategy in an effort to leave my job as a police officer in six years.