Sorry if this is a dumb question, but if two people created a comic can both have the comic registered as theirs? And if they can, how would one go about setting up the comic on the second creators account?

Two people can have access to a comic via the assistant function.
The comic account holder goes into the comic control panel, clicks their comic's name, and on the right hand side of the control setup there's a space where you simply type in the ID of your assistant, then click the "send" button.

There all done :)