2 x 4 is minimum for 2 piggies, but 3 x 3 is the same amount of grids, so i would say yes, not sure on the other for 6 piggies, but would say yes as that seems a very reasonable size.
How is it all going by the way? xx
3x2 or a 120cm cage are the minimum for two guinea pigs so a 3x3 is bigger than that so perfect.
As for the 5x4 I'm not sure