Hi again!
Time for some updates.
I attached Ample Bass P Lite to the bass guitar track, Keyzone Classic to the piano, and routed the drum track through JACK into Hydrogen — unfortunately Hydrogen still can't be used as a plugin.
Here it is:

For now I have everything I need (and yes — tambourine and cowbell are absolutely essential :) ).
I tweaked some drum volumes a bit — still not perfect, but with every new track they become more and more balanced.
I also rendered this whole Ardour - Hydrogen setup to an audio file to reduce CPU load.
The hardest part unexpectedly was the motor sound.
In the LMMS version I used a cello patch with pitch automation to simulate different speeds and that unstable "working engine" feeling.
This time I found a very cool motor-like bass preset in Odin2, but I just couldn't get the pitch controller to work.
So I finally surrendered and switched the preset to legato mode, making the transitions with slides instead.
Not exactly what I wanted, especially for the unstable RPM effect, but still good enough.
Here's what it sounds like now: a preview is attached to the first post update ^
Next time I’ll bring the guitar solos.