Has any of these hypothetical theories a "higher" number of possible universes or has string theory landscape the same type of possible universes than brane cosmology?
Not all possible string vacua have branes in them. For example, heterotic string theories actually do not contain any D-branes at all. They do contain the NS5-brane, but that is not a brane on which open strings can end. Hence, not all string vacua can be brane cosmologies to begin with.
The set of brane cosmologies is the subset of the possible string vacua (so of the string landscape) in which there are large or even non-compact extra dimensions, while the four-dimensional universe familiar to us is attached to a D-brane. This is a funny scenario that could imply that there are other D-branes floating around, containing other universes that may or may not resemble our universe. I think it is somewhat more common for string model builders to assume that all the extra dimensions are small and that the universe is not confined to a D-brane, but the brane cosmology idea is (at present) certainly realistic enough to warrant serious attention.