Admitedly forgot about this thread for quite a while. Apologies for any inconvenience that may have caused.
Anyway: From the evidence presented, saying that Mechikabura swallowed timelines into his body is obviously fine, especially since they are referred to as a part of his "power" and whatnot, though one issue in particular is whether or not to interpret all of that as just being some "pocket" (Using the term very, very loosely here, mind you) dimension that his physical body leads to, instead of containing it outright, which does seem to be the case, given that he still seems to be the same size as the other characters even after this transformation.
So, the dimension itself would be a higher-dimensional space, yeah, but whether or not Mechikabura's physiology would share that nature is a different matter.