I just want to share with you all that we solved our problem with messages not publishing the ground distance.
Our px4flow was not ready for sonar since it was not pre-soldered so we followed instructions in this post:
We soldered TTL jumper in the sonar and on the px4flow board we soldered central pad to 5V to power the sonar.
All as shown in the images of that post.
Now all works perfectly.