Re: Is it possible to populate a General List with new member/attributes via a module/dashboard?
You can't create new members when loading into a module, however an alternate approach is to create an import action with the file loading into the list to create the members + an import action with the file loading into the module to store the data and then putting them in a process that you publish onto the dashboard?
@wquan is correct. I would just add that the module that you load the attributes into should be a system module, a module that only uses one dimension (using the list you are working with). In your planning module, you can lookup the attributes from the system module with a LOOKUP function. The benefit of doing this is that you only have the attributes calculated one time (in one cell) vs being copied X every other dimension.
Here's a link to learn more about the DISCO method (the "S" stands for system).