Outsource it all to a servicing company.

He works with Real Estate professionals and offers full service such as bookkeeping, tax filing and preparation, and etc.

I'm a contractor here in Indy specializing in plumbing, electrical, tile floors, custom tile walk in showers however I offer full service minus HVAC. 

Just call them and ask if they are too busy to handle all the work and offer your services.

So you'll need a few grand in reserve just in case)Also you'll want to have some savings for an emergency.So in short, depending on your area, you could start with as little as 5-10k depending on the price of your property.

We would hold ownership of the units and service them when needed. 

How much electrical service does each unit have?

I think the crucial part of what I'm saying is the research and really knowing your market as well as not forgetting about buying right, and in the right location, not jumping into just any deal, having safe guards like cash reserves, etc I am absolutely no expert and hesitate to even throw this out there.

I own a small construction company where I provide all types of services but am focusing on flips right now.

Not only will the bank give you a hard time about the knob and tube but you will also have a tough time with Insurance companies. a new 200 amp service will probably run you about $2- 2400, rewiring the house, sheetrock, spackle and paint will probably run you another $4-5000, depending on how much has to be opened up and fixed.