Thanks Marian and MaG -
Everything is 100% except for "...Plant in the House"
And the only map location not grayed out is St. Edmund's. So that makes sense. What I cannot find is anything I had not done except what I said above.
So - I will go to a saved game before looking in Helena's room. Thanks for trying to help.
____ Later - - -
I got it. Some time earlier,I thought I had been finished with the pool guy because when I went to talk with him a final time, I got the "look" icon, not the "talk" icon. In fact, the "Look" icon showed when the cursor was on the upper part of his body, but it was meant for the pool. Following that, I had the scene in the lab with David. Some time later I actually did get the last conversation in with the pool guy.
What I never knew was that the final talk with the pool guy is the trigger for the final question with David, regarding the incidents on campus. Doing those things out of sequence created an "invisible" trap, believing I had finished the conversation with David, when in fact the last question wasn't enabled until after the pool scene was at 100%. I hope this information helps someone else someday.