having issues with the deepin store as well and the mirrors for updates being painfully slow. not only that, but i am unable to install anything from the terminal, every time i go to install something i get the failed archive message. and i really do not feel like having to download the source code and compiling every app i want to use or go through the trouble of trying to use outside repositories. so as of now, deepin 15.4 is a pretty desktop environment, but with these issues makes it pretty useless ATM. sad thing is i have been convincing others to switch over to this distro. looks like i may have to start looking for another distro again. please fix these issues because if you do not then they will cause a lot people to lose interest in deepin.
dunkinrunsonyou

Try changing the region for the repository. Replace /etc/apt/source.list with new links from the list of repositories https://www.deepin.org/en/mirrors/packages/

Those apps that don't appears in launcher, if you edit the

OnlyShowIn=Deepin;

and will appears in the Launcher.

The other things that you mention are just at your machine, those errors are inexistent. Try to reinstall Deepin and those errors need to disappear.