Realistically, (If I understand correctly) sounds like he's got a lot more skin in the game and you are gambling a little because you don't have much experience. 

How do I find the most accurate arv?

You can also set it to spy on your phone to keep "date last contacted" accurate. 

Doing them beforehand is a gamble.

I suggest to start with verifying the home is accurately listed on the mls. 

I filtered the list down to just individual owners and extracted their first and last names somewhat accurately using excel formulas.

We got a repair quote for the roof, which turned out to be not accurate.

The information that was provided to you isn't completely accurate. 

I am looking to cater to my fellow servicemembers or perhaps students looking for cheap schooling here.I got viewpoint.ca which is an amazing map of the real estate in the province, but I'm not sure how accurate it is and how to use it as an investor. 

Houses are typically 10%, a building of this size could cost only 5-8% of the monthly income for property managementYou can force appreciation to boost the value of the property, resulting in: Instant equity that you can borrow against to buy other propertiesThe opportunity to sell in 3-7 years for a significant profitHigher valued property means higher personal net worth – a higher personal net worth means you are able to buy higher priced propertiesDisadvantages 15 tenants to deal with15 toilets, sinks, etc. to deal withHowever, with a good property manager at the helm, you wouldn’t have to deal with the two items above, my property manager wouldMore activity because more tenants (again see the third item above)Requires stricter, more focused asset management skills and heavy oversight of your property managerPLEASE NOTE: I made the examples simple to illustrate a point and are not real accurate on the specific costs involved.