So your best bet is to put yourself in their shoes and shop around just like they would be.Also, some markets are definitely seasonal, and your market rent could change drastically from winter to spring/summer.

Your best bet is to get an estoppel that verifies their lease dates, rent being paid, security deposit, and advanced rent.

I bet if they found a subsurface problem, I would own those. :-)ps.

While BP has a rent estimator as does rentometer.com (both allow a few free uses, I believe), I agree with @Zachary Deal that your best bet is to seek out guidance from either the listing agent or a property manager well-versed with the area. 

You can buy those new construction and the rents are strong enough to do ok. 50k to 60k gross by year 2.

Your best bet for that size will be local banks and credit unions, good luck.

Kitchens and bathrooms are always a good bet, but think beyond the basics.

You could build that in phases and finish the first 4 and then get your lender to do a construction loan on phase 2. 

The process is very involved as you'll have to navigate pre-construction activities that involve architectural plans and approval from the city and then the construction activities (Shovel to soil) take anywhere from 5-9 months depending on how much your building. 

Otherwise, the work went OK, but the construction time ran significantly over.