Best way to configure home WiFi with 3 Range Extenders + Xirrus XR-620

ouch. 

The mesh extenders only function as mesh when ran in extender mode. In access point mode (hardwired), they don't function as mesh because they're their own AP and not part of the mesh. They won't be seamless in that mode.

And daisy chaining multiple extenders tends to results in instability. 

Same with using a bunch of extenders.

I tend to tell anyone needing more than 1 extender, to move to an actual mesh system like netgear orbi. And go triband. I'm not a fan of the dual band setups. 

But you can try to make it work.

If you want seamless, you'd want the extender option. The EX7700 and EX8000 will be fairly tolerant of it because of their dedicated backhaul. The EX7000 will have a 50% speed hit because its a dual band. 

Try to star configure them not daisy chain. 

Star:    Extender<----------router----------->extender

                                           |

                                           V

                                       Extender