Contractor for minor rehab

[Pramod Prasad]

First time using a contractor to fix a few issues at my property before putting it in the market. Need to install a water heater, new hvac, fix/replace the front door and install new appliances. Would appreciate anyone with insights on answering these few questions. 

1. What is the typical PM fee (%) for such a job for the GC? I wont be able to manage this on my own. 

2. What questions (critical) do I need to ask the GC? 

3. Any recommendations in KC, Missouri for a reliable GC- looking for someone who can operate in 64130 area.