If you are going to have multiple switches controlling the trim you are going to need some sort of relay deck or controller for the trim motor. If you look on the Ray Allen site they have wiring diagrams that show this. The basic schematic would work for other stick grips as well.
The key point is in a non-relay deck setup the hat switch is used as two single pole double throw switches that are normally closed to ground that, depending on which way you push provides proper polarity to the servo motor to run in correct direction. This is easy to do with one set of controls.
With dual sticks the buttons or switch you push just grounds and input to the real deck/controller so that the controller knows which way to orient the polarity to the servo. In this case the two stick outputs are just connected together at a simple servo deck (either stick provides ground connection) or in the case of a more sophisticated controller both stick inputs are provided separately. The advantage of the smarter setup is that priority is more easily provided to the pilot in the case where pilot says trim up and co-pilot says trim down, etc.
For the AP disconnect you can just wire the outputs together as all you are looking for is to provide a ground signal to the AP to disconnect. Either button being pressed does the trick.
Its a bit more complicated than described but I suggest studying the wiring diagrams and drawing a schematic so you can seee what is going on in each case.
I can't think of a simple way to wire both sticks to be active without some sort of relay deck which is a good idea in any event IMHO.
