DFC 90 Simulation help

I have seen the Fly Level button causes the autopilot to command 0 Pitch and 0 Roll and puts the autopilot into PITCH and ROLL mode, that turning on the autopilot with the AP/FD button puts the autopilot into PITCH and ROLL mode (at the current Pitch and Roll angles?) and also while coupled to the glide slope pressing the GS button puts the autopilot into PITCH mode.  These are the only times I see the PITCH and ROLL modes BUT:

My question is does the autopilot go into ROLL mode if a lateral mode is 'cancelled'  i.e flying along in heading mode flying a commanded turn and the pilot hits the HDG button.  Does the autopilot

    1.  Do nothing

    2.  Go into ROLL mode and maintain the current roll angle

    3.  Go into ROLL mode and command 0 roll.

Same question for the Nav button.

Same question for vertical modes as well.  If in a VS climb and the pilot selects VS doe the DFC90

    1.     Do nothing

    2.    Go into PITCH mode and maintain the current pitch angle.

    3.     Go into PITCH mode and command 0 pitch.

APPROACH mode.  I assume you can select approach mode at any time, to increase the lateral gain. If the pilot does this and a valid ILS signal or GPS approach is NOT detected the lateral approach mode will still be engaged.  

    In this case if the pilot selects the APP button again is the lateral approach mode cancelled and the APP indicator extinguished?

When established on the localizer and glide slope in NAV/APP/GS.

    What happens if I press APP?

        To the APP indicator

        To the vertical mode

        To the GS indicator

    What happens if I select another vertical mode; IAS, Vs, Vs/ALT?

        To the APP indicator

        To the GS indicator

    What happens if I press the ALT button?

    What happens if I press the GS button?

If the selections above take the DFC 90 out of Approach mode and I press the ALT button what happens.

Do any of the answers change for an aircraft established on a GPS LPV/LNAV+V approach.

If the GPS  is in VLOC mode and an ILS then starts to be received (because the pilot just changed nav frequencies or the ILS signal just became valid) and the AP is in NAV mode what happens to the HSI selected course.

If the GPS is set to automatic GPS/VLOC switching and the aircraft is on a leg where the DTK is not the same as the ILS inbound course and the pilot switches to VLOC manually what happens to the HSI selected course.