Try Audacity if there is a version for Linux/Ubuntu. It is free and powerful. It can play MIDI files and direct the data to an output. I use a generic USB to MIDi interface. If your drivers are fine then it should work. I don't know much about Timidity, but I am working on a MIDI player piano project with an Arduino. You may be able to select Timidity as an output from within Audacity, but don't quote me on that as I do not know if that is true. I only started on Arduino a few weeks ago, but I hope that I can help. Feel free to PM me, but know that my response time may be slow.
Hope this helps at least a little!
CadenSeward