The armbian build for dreamcatcher was done by us - not by the armbian mainline team. It is still being worked on and is not currently mainlined to armbian.
The mainline linux kernel has support for all the features the board uses, and so does uboot. That is what the
line means. It doesn't mention armbian.
As far as updates are concerned, except for the kernel and uboot packages, everything else is safe to update. I will be making a .deb repo with dreamcatcher kernel and uboot updates at some point, but the sunxi kernel packages from the armbian repo can't work on Dreamcatcher.
Best way to prevent those packages from overwriting the ones in the dreamcatcher image is to disable the armbian repo in the apt sources - it can be found in the /etc/apt/sources.list.d/ directory. Rest of the apt updates are safe to do.