Were any of the Iceni druids?
Possible, but no one knows.
It would be nice if the site of Boudica's bonfire of her vanity were found, as there could be a million or more surviving teeth from the nimrods who followed her into annihilation -- assuming the Romans and/or the locals incinerated the dead after the defeat. Any major pile of bones that survive probably marks the spot of the battle, and would settle the argument about where it took place.
Also, DNA samples could be plentiful, and shed light on how related the participants were, and what kind of genetic heritage survives in modern populations.