Questions about WiFi Range Extender Configurations

I am trying to understand how WiFi Range extenders work at setup level. I am going thru the specifications and user manuals available on manufacturer websites and it’s adding to my confusion.

I have DHCP IP reservation (against MAC ID) setup in my DIR 615 main router and you can not repeat IP address.

Now I understand that extender translates client’s MAC ID to a Virtual MAC that host router shall see. I want to seamlessly carry say my laptop anywhere in the house with IP reservation & MAC filtering on. I can add both MAC ids to the list but I can not have same IP for two MAC ids. In that case do I need to maintain two IPs under DHCP reservation?

When a client is equidistant from both Router & Extender where will it coect to?

Should DHCP on Extender be tued off and let Router do all the IP Assignment?

Thanks.