You probably wouldn't need a "general" contractor, who (like me), would subcontract plumbing/electrical/HVAC work, though some towns permit HVAC work to be put on a general "building" permit.I'm not entirely sure what plumbing and HVAC work the previous contractor did but you may (sometimes) have issues with plumbers and HVAC guys taking over or signing off on work done by previous contractors that they can't or don't want to put their name behind (or they may charge you more simply for doing this)... depends on the company/person, and on the nature of the work done.

J Scott, No we do not charge for any management time that was a typo. 

One of the great things about them is they charge by the month and you can change your policy and terms on a monthly basis also.So, yes, you'll pay a higher premium for any month(s) the property is vacant. 

Are there ways to automate the payment process of monthly charges?

Would you charge them to move the provided fridge out and back in again after they move?

Rather than sharing a commission, the agent is just reducing what they charge.

New water heater, new stove, new fridge, numerous repairs, and a water leak emergency that I should have fixed on my own but went with a company who charged me $700 to fix something I could have done myself for basically free.Now, I probably have a bit of a crappy house with all the things that have gone wrong with it, but I also had super conservative estimates behind my CAPEX and maintenance.

What is the rent you're charging for this one

You can hire an electrician to install GFCIs, and charge the tenant if they would like.I would have a plumber address the leaks as soon as possible.

I mean most places charge $200 just to show up then the rate on top.Take the disposal out and just pipe it normal.I remember my landlord replacing mine often in college.