This grid is not really a unique solve. Twain can be sorted under '19th century novelists' while Eliot can be sorted under the 'pen names' category. This creates a perfectly correct and legitimate alternative solution to the puzzle, which effectively breaks the grid.

Thank you for the feedback. The connection is technically “Victorian novelists” but you can argue that Carroll, then, could switch with Eliot. I’ve changed Eliot to Brontë.

I enjoyed this generally, but I think "victorian novelists" is a pretty crummy category

Austen doesn’t fit in her group as she didn’t live in this era.

Alright, Austen's out too. Hardy's in. You got me.