Radio commands are being redone according to the previous developer update. I guess they eliminated the ones that haven't been fixed yet from the menu to cut down on the amount of confusion, eg "if i tell my flight to change formation they do it, but if i tell them to attack a specific target they don't, what's happening?"
In other words, i'm keeping my fingers crossed the rest of them will be added in the next patch.
As for landing, if the airfield is equipped with an airfield AI module (this is done in the FMB, in other words the campaign maker must have included this feature when building the missions for it to work) it will automatically start handing out landing clearances to your flight once you overfly it. It will also mark the active runway and direction with a "T" marker as the touchdown point, correctly taking into account the current wind conditions.
Your wingman will stay with you and fly low and slow while you land (and often stall and crash into you), so it's a good idea to engage autopilot and time compression until it's his turn to break off for his approach or you see the autopilot placing your own aircraft in the landing sequence. At that time you can go back to normal time, disengage autopilot and land as usual.