3.1 How can I output midi events to an external midi device?
Use artscontrol, go to the midi manager, choose add OSS midi output, type
/dev/midi00 (or something else), and connect the Brahms entry to the newly
created midi port.
3.2 How can I use aRts synthesis?
The easiest way is: use artscontrol, go to the midi manager, choose add
aRts synthesis output, and choose arts_all. Connect the Brahms entry to the
newly created synthesis instrument. You can change the instrument using the
midi instrument selection in Brahms then.
3.3 How do I write a Brahms plugin?
Just look at existing plugins. Extending Brahms is really easy.