Thank you @ich777 for resolving the wget URL issue. I am able to start the SCP server now. One other issue @Atomic Bomb mentioned above, I have noticed is that the config files in appdata\scp-secretlaboratory\ConfigTemplates are only read once during docker creation, or recreation. If you reboot the server, any changes to these files are not read. The workaround is to edit the docker template, and once applied these files are read from.
Is there a different location we should be editing the configs?
SteamCMD: /mnt/user/appdata/steamcmd
Container Path: /serverdata/steamcmd
ServerFiles: /mnt/cache/appdata/scp-secretlaboratory
Container Path: /serverdata/serverfiles
EDIT:
It looks like MultiAdmin pulls from the ConfigTemplates folder initially, but you need to edit scp_multiadmin.cfg to point to a specific config location. I then created \appdata\scp-secretlaboratory\Config and rebooted the container.
Edit the content of scp_multiadmin.cfg:
config_location: "Config"
How to configure MultiAdmin:
https://github.com/ServerMod/MultiAdmin
Now changes to the server config files take after a reboot!