What percent is standard that you use towards "emergency repairs etc" after the tenants pay rent and after mortgage.

I would say that your going to want at least $10,000 in reserve in case you have to make a major repair, have to pay the mortgage if not all the rooms get rented, and expenses you didn't account for. 

Google for their phone numberChapman Painting 13115 Meadowmere rd Huntersville,NC 28078Good luck!

New roof and windows needed along with some minor foundation repairs.

In other words you receive a 30% tax credit on the solar system as well as a 30% tax credit at the least on the roof that is under the solar system (full roof 30% depends on the advice of your CPA).Couple that with the roof now becoming a producing asset and offsetting the utility bill instead of a liability and the increase in appraised home value assuming the solar system is not leased then going solar makes a lot of sense at the same time as replacing/repairing a roof.

With the amount he has in his account and no mortgage he should be able to handle vacancies and repairs, this is a valid point, reserves are essential. 

I have a tenant already in place and just renewed their lease for another year (end of Sep. 2019) at 800/ month.I will put between 200-225 a month aside for cap ex, repair, vacancy, etc.

Property has been neglected and I have concerns about plumbing as house is 70 years old and it was neglected by previous owner who simply did patchwork repairs while never addressing the problems.  

I think it’s a little much right now to repair 12 properties.

I'm pretty sure they don't allow the 0% down loans on multi-units (up to 4) as other owner-occupied loans do.You'll still need savings for any surprise repairs as well as the closing costs.