Now i see what you dont want the pp to affect the HUD. 
But, i’m not sure if you can somehow exclude the HUD from color grading. There may be a way with render custom depth option using a post process material but i’m not that so good at advanced pp materials so you may want to ask about it in the Rendering section of the forums.
Thanks for the screenshots, btw, and dont forget to put them in your fprum post as well!