12" Speakers are common in bass cabs. High Freq. horns are also common in bass cabs, but it isn't as simple as saying bass cabs have 12s and guitar cabs have 12s so everything should be fine. There are other speaker parameters that need to be considered. Mostly excursion. However, I am not an expert, which is why I asked the question in the first place.
In the end, I ended up getting a dedicated bass cab as the Powercab did not provide the sound I needed for bass using either raw or flat to allow the Helix to shape the sound with Cab emulation, or IRs.
Thanks for the help, everyone.
-Ed R.