Squid

It looks like the network stats plugin automatically tries to download the package on every boot, instead of saving it to the flash drive.  In your case, the network isn't completely up at that time and it fails.
 
Ignore the error (it's harmless), Uninstall and reinstall network stats.  And post in the support thread

Yes, with 2 caveats
 
Virtual Machines if you're utilizing passthrough.  This will require you to reconfigure the devices, ACS override settings etc to match your new system If you utilize on either the old system or the new system a RAID controller set to JBOD mode which changes the serial numbers of the drives will require you to reconfigure the drives since the S/N's may change. Can't tell if you fall into #1, and it definitely looks like you won't fall into #2

You've got an old version of the template that had an issue in it.  Edit the file /config/plugins/dockerMan/templates-user/my-homeassistant.xml on the flash drive and the line that says
<TemplateURL>someURLhere</TemplateURL> change it to
<TemplateURL>false</TemplateURL>  and the devices will not come back on updates.

OTOH, give it more cores.  Minimum requirements are dual core, but *technically* you're only giving the VM a single core (with a HT)  Also wouldn't be a bad idea to enable TPM within the BIOS (It tends to be disabled by default) 
 
What is the CPU you're using?

Settings - Date & Time - also set up the NTP servers (time1.google.com, time2.google.com, time3.google.com, time4.google.com)

By design it has to be a remote path in the template.  After the initial download it is saved.
 
If you can't upload (or find) an image you like remotely, then you can manually copy the appropriate file to /var/lib/docker/unraid/images with the correct naming

I think the system is getting confused with the fact that you've got a br0 and a br1 set up, but br0 has no connection.  Not a networking guy, but probably if you delete /config/network.cfg and /config/network-rules.cfg on the flash drive and then reboot (and then in settings change the IP address back to 10.100.1.100 / Gateway 10.100.1.2) it'll start working fine.  (Either that or use the other ethernet port)

Not really.  They're both identical.

Have you done this:
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/page/2/?tab=comments#comment-819173
 

The docker image is completely empty.  Probably due to whatever you were doing with the previous problem.  Apps, Previous Apps and check off what you want.  5 minutes and it'll be back to normal.

Just stop Docker (settings, docker)  Then delete the image, then re-enable the service followed by Apps, Previous Apps.  Check off what you want and you're done in 5 min

Dec 13 05:02:32 SimServer kernel: FAT-fs (sda1): error, corrupted directory (invalid entries) Dec 13 05:02:32 SimServer kernel: FAT-fs (sda1): Filesystem has been set read-only Try rebooting if the system during it's checks on bootup can't fix it, then pull the stick and run the file system checks on another computer.  You might also consider restoring your backup (if you have one) onto the flash drive.

https://forums.unraid.net/topic/51703-vm-faq/?tab=comments#comment-557606