Don't be afraid to paint the ceilings! Painted ceiling can really bring the room together, many will refer to it as "the fifth wall". I like to choose a complementary color in a shade or 2 lighter than the wall color to use on the ceiling. Yes, flat tends to be best for ceiling, but I rarely use flat paint on walls, even the bumpy ones, I think a semi-flat or even eggshell would look nice. Good luck!

Very helpful. Thank you for the response!..