Filled grid, stared for hours, identified the poet who I knew for sure had a poem called the "Theme Word", decided he was scattered rather unfairly in the grid. His poem is - absolutely - a couplet, and only a couplet, but not resolvable with "letters initially observable". gave up on trying to find the other poet, assumed to be similarly distributed. Knew I was missing a trick.
Left it four days, came back, spotted the answers to each challenge almost immediately and resolved all issues. The first occurrence of one of the features can't realistically be entered in the grid as described, so I'd submit the second if I were to be a) on time and b) bothered.
Was the red herring intended, perhaps even an aborted third reference? We won't be told! Messed me up something shocking.
friendly greetings to all