As you can see, all the MIDI channels are now visible, and it would be easy to edit all info from the WEB GUI.
However, if I need to unselect the active users and select an inactive one to gain access to these settings, maintaining these Program Changes from the WEB GUI would be a bit cumbersome...
The problem here is in your use of the MIDI devices. You set up two MIDI devices and specified ports for both of them, but in the MIDI preset shown in the first screen shot, you left the port set to All. Since there are no MIDI devices set to All, no devices are available for this preset to send program changes to. When you change the user to Geir, that user has been assigned no MIDI devices, so that user sees all 16 generic output channels.
The easiest solution is to change the MIDI device ports to All so they match the port setting on your MIDI preset. I recommend not setting specific MIDI ports anywhere in the app unless you need to, because then you won't have to worry about making all your port settings match.
After changing the MIDI device ports to All, you will only see channel 16 available to send program changes to, because you have only given the Einar user access to the MIDI device that uses channel 16. If you want the Einar user to edit the program changes for all the MIDI devices, you can edit each MIDI device and make sure Einar is selected.
Note that you don't have to set up MIDI devices at all; if you don't, you will always see all 16 channels on the MIDI preset edit page. But it's a good idea to use MIDI devices because that allows you to change the channel that a device uses without editing all your presets.
Regarding the Import/Export of these settings, this would have made it easier to set several channels at once.
It would also serve as a nice way to backup and store a copy of these settings in case something gets altered.
You can undo changes from the left column of the MIDI preset edit page in the web interface, or from the Settings > Account Sync > Rollback page in the app. I think this is better than exporting/importing an entire file because it allows you to undo earlier changes without losing any later changes you made. In other words, if you find a mistake that was entered two weeks ago, but several correct updates were made since then, you can undo the mistake while preserving all the correct updates. Another reason it's better than exporting/importing is that it's automated and doesn't rely on you remembering to make regular backups.