Seperate scaling (potentially to 0 with wake-up on HTTP ingress perhaps) and accounting. You could probably also host one deployment and 'vhost' them on /var/www/vhosts/<sitename>. If you go the proxy route, consider running just one varnish server, with backends per site, in stead of nginx.

don't know if you want/need the websites baked into the docker images, but I frequently forget and re-discover that 'Docker Images Aren't Real', just collections of layers, and 10 images consisting of a base layer with website files on top are not 10 images, but just 11 layers..

generic 'webserver' nginx that serves out of /var/www/, make 10 deployments with that image, connect different website file volumes to /var/www/ per deployment?

Ooh, someone with the exact screen and Mac OS! Do you have aliasing bugs in Mac os as well? If you fixed those, how?