How would you prep and paint freshly hung drywall?

I have a wall pre-painted in latex. Can I do the final criss-cross pattern with the suede paint over the latex, or must I first cover the entire wall with the suede paint?

Do you have any tips or information on painting the brick on a house? I have a house that has orange brick and I was trying to figure out the best way to paint it a light gray to match my trim and siding. Is it recommended to paint brick,