Just a quick note about DLNA. I have tested it and it worked wonderfully for me. I just activated it and waited some time for all files to be indexed. With a modern Android mobile phone (with DLNA support) I was able to play videos in many format (included HD MKV videos, of course downscaled to the resolution of the phone display, but it does not matter).
I started with the DB in RAM and then changed it to the custom path (I put it in /opt/var/run). I saw from the config files that MiniDLNA is using inotify to be notified of new files, which is great.
All in all, I'm surprised that it was such a flawless experience. Thank you very much, TeddyB!