1) ah, ok you want back to primary gps. I don't know if kplex has this option. Maybe you could ask for this in kplex forum. You could set the failover in kplex and set a trigger in OP to detect if lat or lon are not present for x seconds, and add an action to reset kplex.
2) You can. Set a switch xxx in OP. Connect the switch to GPIO pins. Create a trigger: "if switch xxx is on..." set an action "start wifi AP"; create another trigger "if switch xxx is off..." set an action "stop wifi AP" and that's all. You could do the same with mqtt to create virtual switches in your phone.
2) You can. Set a switch xxx in OP. Connect the switch to GPIO pins. Create a trigger: "if switch xxx is on..." set an action "start wifi AP"; create another trigger "if switch xxx is off..." set an action "stop wifi AP" and that's all. You could do the same with mqtt to create virtual switches in your phone.