Any tips for properly running the numbers for both?

It should last a very long time as long as it's properly maintained. 

I have a partner that is willing to co-sign because he has proper paperwork including these pay stubs.

Because if you look at the cash you receive through a refinance as "free money" you are unlikely to treat it properly. 

A skylight that's properly installed with the right sealants shouldn't have any immediate issues. - Be prepared for maintenance.

I am in the learning phase, right now I am figuring out if I using this calculator properly. 

The proper chain of events would have been:Tenant hangs clothes>clothes fall down>tenant notifies you via your trouble ticket system (formal, text, whatever) that shelving fell down > you fix or arrange for someone to fix shelving and thank tenant for letting you know. 

This is a good time to start bringing a team of professionals on board to help keep your project cost effective, completed to the proper codes and standards and completed in the shortest time possible.2.

Deal sourcing: If Brokers aren't taking you seriously, then you're not approaching them properly.

I'm just wondering if he has just up and left (owes 2 months rent) What is the proper procedure to legally clean out and re-lease the unit.