Specific bracket for derailleur groups?

Okay, this will be quite an introduction 😅
We have these two lovely cargobikes 🥰 At the left an original Gazelle Cabby, om the right a rebuilded Cabby (not by me, bought it from a in between owner, so I don’t now the rebuilder).
The rebuilded Cabby has a much bigger chainring, derailleur 3×10 (hub&derailleur Sram Via gt combi) in stead of Nexus7, disc brakes in stead of drum brakes. In short words: it weights 25 kg in stead of 38 kg and rides like a charm 🤩 But… The steer of the rebuilder one isn’t handy with children, we cannot attach our beloved FollowMe tandem and the raincover doesn’t fit because of the steer.
The original one is practical obviously, but so heavy with alle the wind in southwest of the Netherlands 🥴
So neither of them are perfect for us. Making the rebuilded one more practical will cost to much money for a 10 year old frame we think. So I am discovering options to rebuild the original Cabby to make it lighter and smoother. But this will be quite a puzzle.

The first thing I wonder:
When I dive into derailleur groups it appears that you have to have specific coordinated Srm/Shimano/… bracket, cranks and chainrings. But.. my rebuilded Cabby appears to have the original bracket and some random/re-used cranks and chainring?
If I have to have a specific bracket, I have the first problem: the Gazelle Cabby has a rare bracket: a pressfit bbs08 (see last picture). How can I make that work for the right chainring and cranks?

by Elisepoester1416