Hi Chris,
Correct me if I am wrong do you mean that you want to create another module that can search both joomla article and EasyDiscuss?
Not sure if this is necessary, because you can achieve this by using Joomla smart search module
https://take.ms/XRMAT
Make sure you enable
Smart Search - EasyDiscuss Discussions plugin in order the discussion got indexed and display in the search result.
And make sure you enable
Smart Search - Content as well for indexing Joomla's articles
If I misunderstood you here, can you explain more in details, perhaps, with some screenshot might help us
Thanks for your cooperation and understanding Chris