I like Bluebell. I don't think he was a minor character: like mfrengle and Vesper said, he managed to keep Holly going following Sandleford's destruction. Later on, he also (unintentionally) provided Blackberry with the idea to use the boat to escape from Efrafa. He played a really important role in the original book.
...which makes it even more disappointing he was left out of both the film and the series. He didn't even appear in the
radio drama! It seems he will appear in the new miniseries, though, voiced by Daniel Kaluuya.
However, Buckthorn, Acorn and Speedwell didn't appear in any adaptations so far either, and according to IMDb, it seems none of them will appear in the miniseries...