I'm not 100% sure I understand exactly what you are attempting to accomplish but here's a few tips:
The journal object generates the emails that are sent out so anything you do to the templates to modify the displayed values of the journal records would also need to jive with what your mail server is willing to send (on a protocol level, not a "what I see in Outlook" level).
Also be careful when sending with a from address that doesn't point back to one of the listeners as any replies to the email will not make it into ISM.
That all being said, you can update your templates to use the contents of any field on the parent BO or any function to call the "Current User" information:
https://help.ivanti.com/ht/help/en_US/ISM/2017/Index.html#Reference/Functions/_Current User Functions.htm?Highlight=current user