I have gotten a response from PressReader, confirming only so far that I can authenticate up to 7 devices on one account.
I am still unclear on how to read on a desktop computer when my family is pretty much Microsoft-free (Linux), basically meaning that we'd be stuck using pressreader.com instead of their apps.
And again, how would subscribing to two completely independent subscriptions at the same time affect my ability to read both?
My local paper at
http://stcatharinesstandard.ca/ provides a "free" 14-day trial. Perhaps somebody who is already paying thestar.com their $9.99 monthly can try this out, find out how to read more than one subscription with a single PressReader tablet app. And without spending $30 for the unlimited content subscription.