Plumbing- corroded cast iron drain lines, corroded copper piping that leaks, sink trap leaks, sink popup ups that are non-functional.

You're going to need to show negligence, so make you you have documentation of prior times it has leaked. 

A large limb fell and busted my roof.

Mostly just went with my gut I bought it during a crazy time single family homes are being bought only hours after coming on the market I had the choice between this house and another the other was slightly bigger with a basement in the porch but the roof did not seem bonded in my Spidey senses told me there might be Foundation issues in mold due to a smell while inspecting the house admittedly the house I bought is 950 ft has no basement and is a two bedroom one bath with a detached garage How did you finance this deal?

(Roof, ac, flooring, etc etc. ) that should make you even closer.

Lastly, is it possible to put a “seal” on a current shingled roof, should there be any leaks?

I would like to get a quote for insurance.6 unit single story building.  1960's construction, all brick exterior, cement slab, and new asphalt shingle roof. 

What major expenses can you expect in the next 5 years (eg roof, HVAC) for each property? 

Buildings are all brick, roof replaced in 2020.

This is not only to make sure that people are taking care of the property, but this is also to make sure that tenants aren't overlooking issues that could be addressed now that cost way more later.These can be minor roof leaks, gutter leaks, mostly to do with water penetration.