You can paint it but the brick pattern will still show. Would look a little off closeup.
Yes. I would use masonry/concrete dye/stain which can be mixed almost any color(s).
It permeates the masonry/concrete and cannot chip nor peel, assuming the actual surface is clean (power wash) and not spallling (old concrete can do this).
You can apply it all kinds of ways, ranging from a spray bottle, chip brushes, to sponge rollers and sponge brushes.
You'll need to think about applying the lighter colors first, as unlike dying fabric, you can’t bleach this color out, if you make a mistake.
No, unless you totally redo. Coloring it or painting it will still look like brick., just a different color.
Thanks to all