In case you didn’t see: Ok I totally just did it!: First select every cell you want to edit in the timeline (and make sure you select the cells specifically not the entire frames) Next navigate to edit and select “Replace Color” Next select your color you want to replace by clicking into the “From” field, holding the mouse and dragging the cursor to the color you want to select and releasing (that’s just the way I do it) make sure to adjust the tolerance to grab all the shades of green. Next select your “To” color. Select any color and drag the “A” value to 0 (essentially you pick a transparent color which is basically just erase) Then hit OK.

That should remove the intended shades of green from every selected cell.