You can have other schticks in but only one 'type' of schtick functions at a time, so if you use your sabre, only the sabre schticks will work; if you punch someone, only Combat schticks.
Some people work well by, say, having Combat Schticks in for emergency defence (if you don't attack at all in the turn, you can just choose which type you are using) or some have one or two Gun schticks in, tap them all first turn for quick kills with their guns and are already ready to switch to sabre the next turn as they swap the gun schticks out for their other sabre ones.
The main limiter is that it takes a action to draw a weapon (though not a lightsabre) so if you are going to mix in combat schticks you generally use unarmed ones, as you can switch to them without penalty. If you have Gunslinger, you can switch between a sabre and a pistol with no penalty also, which is a neat trick (like Luke at the end of ESB, with a sabre in one hand and a pistol in the other), allowing you to choose openly each turn whether to shoot or slash.
It's only one swap a turn, I am afraid, though as you've gone a few without swapping I can backdate that as it were. Bear in mind you don't have to swap in when you swap out, so you can just leave in blanks (many templates don't have the schtick variety you do).