There is unfortunately not much we can do here, your problems seem to be either with Micasense and/or Pix4D.
The only thing we can say is that the Wifi being weak doesn't prevent you from taking pictures. The wifi on Sequoia is for configuration only, its power and range are way smaller than Bebop's one. We estimate it at 10m (30feet) so it is not meant to be used during flight (not like the streaming on a drone for example). Once the camera is properly configured and the acquisition is running, the connection with the camera can be lost without causing the acquisition to stop.
Regarding the Pix4D app, I suggest you ask them directly.