I started writing this song trying out a new workflow to program drums in Ardour (a free and open-source DAW). I have a MIDI buss with a multi-sampler, each sample going to its own audio track. This way I can have multiple MIDI tracks sending notes (eg, one for each drum instrument) to a single same plugin, while being able to process each instrument independently in its own track.
As for the instruments, in this song I play a Fender Precision Bass through an Elektron Analog Drive, and a Gibson Les Paul Studio guitar through Guitarix (https://guitarix.org/). The piano is a free soundfont that I play through my MIDI controller, an Arturia Keylab 61.
The drum samples are low quality (since it started as a test), and I could spend more time improving the mix, but I'm happy with this one.