I have several of these french doors in my house that use the multipoint locking system. Mine are Pella brand and the “architecture series” I hear that the newer models can be bought with instinctive technology, but it is not possible to upgrade my doors. I have tried calling Pella and talking with lower and there are no after market locks that really fit. The frustrating thing is that it is quite easy to leave one of these doors unlocked and it can be difficult to tell from looking at the door if it is locked or not. I decided to use the ecolink contact sensors to report the lock status of each door (others have done this with standard dead bolts. It does not allow you to lock/unlock remotely, but it does give you an update when the door is unlocked. I used a small switch from radioshack hot glue gun and a bobby pin that I wrapped around the lock cylinder. when in the locked position the bobby pin holds the switched closed.
I have the same doors and have the same issue. I didn’t quite follow the logic behind your project though, at least to the detail of being able to replicate it. Would you mind sharing more details and/or pics? I’m excited to see that someone actually has a working solution for this.