Docker-compose.yml start rclone mount and webgui at docker starts

I'm afraid I can't help you with docker-compose - I don't know very much about it.

Yes it is possible, but you have to use the rc api to start them off.

https://tip.rclone.org/rc/#mount-mount

If you want to pass parameters to the mount you'll need the latest beta

See also

For how to pass the params