Looks neatly finished so far - Except for the small "CPU-FAN". Since the thing is only attached with two screws - completely warped and sounds accordingly...
Basically it is mentioned that no updates may be pulled from the official Ubuntu Repos. But what if I want to install additional packages like anydesk? Need an update from the libgcc1 etc... and apt cache update and more packages?
Adding more packages should be fine as long as you don't update any current dependencies that the Apollo software uses. Give it a try; worst case you need to reflash your SD, no big deal