Changing management companies

[Christopher Short]

Recently put in an offer on a fourplex in the greater Killeen, TX area. My offer was accepted and we are currently under contract! After looking over the rent rolls and leases, I am considering changing management companies. I will be house hacking my fourplex; currently all units are occupied. One  of the leases is ending in December (this is the unit I will move into). I would love to hear from others who have changed management companies following the purchase of an investment property! Some of my questions regarding the change of management companies are:

-How does this affect the current leases? 

-If one tenants rent is significantly lower than the other three, am I able to raise that person rent to match the other three? 

-Is there a cost to change management companies?

-Since I will move into one unit, should I pay “rent” to the management company in order to keep a history of payments?

Any and all advice is welcome! Thanks ahead of time!