Sounds like you have a pretty good setup. Check out Plex for organizing and displaying your media which also makes it accessible to all DLNA enabled devices within your LAN.
I have a Synology media server with 7 terabytes of media with Plex running and connected to the Mikrotik. Of course it is accessible by any device connected to my LAN. I have separate Roku 3s on every TV so everyone can watch what they want and the remote even has earplugs so we don't drowned each others enjoyment out.
__________________
|