1. Maybe, if you want any skin to be added and they are not too large then you can suggest it here. We removed bunch of custom skin in last few updates to reduce the size of download since it takes too long to download them with VCMP client.
2. Rejected, it require us to add whole weapon to do that. Example: If we were to add 3 more different new sound of M4, then we will have to add 3 whole M4 of same model with different sounds. The size of files that need to be downloaded by players will eventually be too large and after considering the slow download speed of VCMP client, i think it's not worth it.
3. I'll reconsider this. It's OP but if the cost is high enough then players will use it wisely, it's quite good to be used with Suicide Vest and Hydra Bomber.
4. Rejected, it will cause confusion since teams are based on colors. If everyone can chose what ever colors they want to be, then how can you tell which team the player is in..