Rigify FK bones for horse legs are wrong, is it possible to fix that?

I modified the main deformer bones of the rig (layer 30(counted) /29 in the tool info on the armature window) recently because there were some joints missing and also there were some areas I wanted to have better control over.

However, I had to find the hind legs (probably the forelegs as well) being non-influenced by the FK rig and I really have no idea how to fix this.
Also, the rig appearantly seems to miss those extra joints I added manually. I am hoping anyone could show me a way to fix this issue so that I can continue animating. It could also be that I just didn’t notice any minor errors I did while editing, so if it’s simple ideas you have got, feel free to inform me so that I can check if I need to change anything there.

Thanks for reading.

If you add/remove bones manually or just generally mess with the hierarchy, how can you expect it to generate a proper control rig on top? You can only adjust the existing bones or add predefined body parts from Properties (Window) > Data > Rigify Buttons while in armature edit mode before generating the rig.

Alright, I try to do so. Where can I get more detailed info about that? I see the layers in edit mode, but they quite confuse me at the moment. (Opened up the pre-generated armature.)