OK lets go through your issues:
RoamingEnable 802.11r/k
Look in to setting your bssminrate value lower using the CLI - this vairies cdependant on what platform you are using i.e. ZD or SZ/SCG
Look in to using smart roam:
https://support.ruckuswireless.com/answers/000002277Use OFDM channel only (unless you have legacy clients using the network)
5GHzClients by default all connect to the 2.4GHz radio. This being the case there are two ways to get clients to connect to the 5GHz radio.
1. Set up a 5GHz SSID
2. Configure the Band Balancing percentage value to 0% (ZD and SCG platfiorm only).
SSID'sUnsure who you talked to in supoport but your option of having a SSID which will broadcast only a 2.4GHz SSID is achievable by means of WLAN and AP Groups
If you need anythign welse like a guide to how to set up the WLAN and AP group just let me know and ill do one after the holidays.