You don't provide enough info to be sure about this. We would need to know what mobo maker and exact model number you have, and same maker / model into for those fans. What I can suspect from your description is that you have fans with Addressable RGB (aka ADDR RGB or ARGB) lighting units in them, as opposed to plain RGB system. Those are two incompatible systems. One symptom of an ADDR RGB lighting system that only shows green all the time is that it is getting power but no control signals.
Whether you can control the RGB effects on your existing fans depends on what type of RGB header your mobo has. That also will determine what it might be able to control for the lighting STRIPS you want, so you need to know that before buying.