Questions about Thule Additional holder for RideAlong

I can't answer that, I don't know

Man muss 15cm zwischen den Rohren haben. Diese Anleitung ist super-nützlich https://support.thule.com/hc/en-us/articles/360009116220-How-do-I-know-if-a-Yepp-or-RideAlong-child-bike-seat-will-fit-my-bike-

Yes, they are there

I don't think is the same mount, it is for the Thule Velositz RideAlong Lite

According to research, these are not available to buy separately.

It is for the "Thule RideAlong", as shown in the description. The one you are looking for is the "Thule Quick Release Bracket" according to the manufacturer's website. Unfortunately, I haven't found it in the Galaxus range. However, you could contact the customer support and ask for a possible inclusion of the product.

Bracket and screws are included. Fits perfectly.