I have a TINY Zigbee network. 9 devices today, 4 of them are Hampton Bay Fan Controllers (HBFC.) 3 of them are repeaters(1 Peanut, 2 Iris). But the day I started down this path I had a Peanut and an Iris Motion sensor v3.
Home Depot doesn't carry these items in stock around here so I ordered one to try. It worked and I ordered three more. Having read all there is to read on those HBFC it was clear I'd need repeaters. So I stopped by Lowes and bought both of the Iris plugs they had. I deployed them in the rooms where the fans are and waited for Home Depot to notify me of the arrival. In other words, my Zigbee network had plenty of time to settle out... not because I'm a patient guy, but because Home Depot is not Amazon Prime. 
When the HBFC arrived, I paired it and installed it. Elsewhere I mentioned I have small switches tucked into the canopy and I continue to use them with the HBFC. First one paired and worked first time and was such a good experience, I moved directly to ordering the remaining 3. They arrived and got installed and all worked perfectly, first time. It was all due to reading that I really needed repeaters, buying them and using them.. and luck in the placement. Ihave one Iris plug installed in an outlet that is on a common wall between two fans so I got away with one repeater for two fans.
I hate the ugly wall wart plugs. They are a failure just waiting to happen because both my wife and kids do not understand mesh and will unplug them so they can charge up a tablet/phone.
I purchased two GE Zigbee in-wall dimmers and replacing ZWave dimmers JUST so I could unplug those wall warts. One worked great. One pretty much doesn't. It works fine as a dimmer, just not as a repeater because it's LQI is a dismal 25 vs everything else is 252 and above.
Neighbor Table Entry
[peanutPlug01, 3190], LQI:254, age:3, inCost:1, outCost:1
[MasterBed WallDimmer2, 7454], LQI:254, age:3, inCost:1, outCost:1
[Hallway Dimmer, A66A], LQI:24, age:7, inCost:7, outCost:0
[Outlet 2, D714], LQI:255, age:3, inCost:1, outCost:1
[Outlet 1, DC3C], LQI:254, age:3, inCost:1, outCost:3
I mentioned I'm not Mr Patience, and so I unplugged the wall wart near one of the HBFC after the "HallwayDimmer" had been installed. I clicked the Pico to control the fan near by and it worked and I smiled and put the wall wart away. 30 mins later the fan could not be controlled. That's when I found the low LQI. Plugged the wall wart back in and 30 mins later it was all fine. I never had to do the horrific dance to re-pair. I just had to be patient.
I need to swap the Zigbee in-wall dimmer because it's GE therefore probably bad. But the (to me) big news was NOT having to re-pair. It happened multiple times because my first reaction to the low LQI is.. I didn't pair in place, I need to reset. I disabled the Zigbee radio for 30 mins and unplugged the wall wart. I then enabled the radio and when it all came back, that fan was back to unusable. Plugged the wall wart in again and 30 mins later it was fine. In other words. I spent some time trying to make that specific Zigbee dimmer work (LQI= 254) like the other. Each attempt yielded a "lost" fan that reacquired itself after 30 min.
I hope this helps by adding to the community knowledge of these Fan Controllers. Mesh weakness aside, they work just fine. I have rules that take MultiSensor6 temps and turn the fan on and off in each room. There's a Pico in each room and the Push-and-Hold "layer" controls the fan. (off-low-med-high.)
