I tested my Dockerized Mumble-Ruby-Pluginbot setup on a „512 MB / 20GB SSD / 1000GB Traffic“ Virtual-Server from DigitalOcean for 5$/month using the „One-click app“ on „Docker 1.12.3 on 16.04“.
Playing three bots simultaneously is no problem but it becomes laggy if you start downloading/converting videos or search for videos for with the yts command.
If you plan to do CPU intense tasks stop one of the bots.
While this screenshot was taken all three bots played music:
I used the development branch of the bot.
If you want to try out the Dockerfile see here.
More information about the Mumble-Ruby-Pluginbot can be found here.