With UniFi access points I found 802.11r to be unnecessary. I lowered transmit power so each room only has one AP providing a -67 dBm signal or stronger. 802.11k is enabled by default and is especially important if you use DFS channels. You can enable 802.11v with the BSS transition setting. I verified with Wireshark that my iPhone requests a 802.11k neighbor report, the current AP responds with a neighbor report containing a single candidate AP, and my iPhone roams to the next AP. Internet phone calls do not drop when walking between rooms. That is the only application that requires seamless roaming.