Confirmed.
When you have a pistol it doesn't show in your holster.
Even when you switch from rifle to pistol and back the holster stays empty.

Afaik that edit button is there to change settings/options in a mission if there are any.
Like respawn times, number of respawns, time of day that kinda things.
But that's only available if they are scripted/added in the mission.

Indeed (for now) there's no "eject" action when in flight and no "halo" either.
My guess is that this is just not added yet...

I think "Space" also works...Not entirely sure though.