Alternately, run OpenWRT on the APs themselves, and then you just need one provisioning protocol.
Does it support seamless roaming of clients between group of APs?
Last time I've tried, it was not supported by any open source solution.
Well AFAIK the core seamless roaming in Unifi is using hostapd, which is the same AP software you use on OpenWrt. See 802.11r Fast Transition.
I think it should even be possible to get seamless roaming between Unifi and OpenWrt with correct configuration of hostapd.
Does it support seamless roaming of clients between group of APs?
Last time I've tried, it was not supported by any open source solution.
Well AFAIK the core seamless roaming in Unifi is using hostapd, which is the same AP software you use on OpenWrt. See 802.11r Fast Transition.
I think it should even be possible to get seamless roaming between Unifi and OpenWrt with correct configuration of hostapd.