[lathspell]

As said above, Beorn was dead and Grimbeorn, his son, and his people were fighting Dol Guldur and holding the Anduin Vale which holds the most used trade route.

The BW's: I guess they never knew anything about the War. I don't doubt Sauron still could use them as slaves, yet how could he reach them? He himself going from Mordor to the Barrowdowns? No, he was Dark Lord and Lords don't do such things, they've got slaves for such errants. yet the Ringwraiths were to stay hidden and crossed the river only at the latest moment. They did pass the Downs, but then there was no time for they thought they almost had the Ring, 4 hobbits and a man alone in the Wilderness against the Nine. I don't think the BW's would take orders from any save from these ten.

Radagast: he played a small role in the Books, but I don't think he was that unimportant in the War. First, he was one of the White Council and they practically made the difference, with the assault on Dol Guldur and all their wisdom. And he was the one that had many birds and beasts for friends, so he had probably more spies than any other of the Council, retrieving the most information.
In the Hobbit Gandalf is the only one knowing that the orcs and wargs are coming at the Battle of the Five Armies, and I do not doubt that this information came from Radagast. Maybe he had had contact with the Eagles or other birds.
I don't think Radagast's power was in fighting, but in gaining information. Like Elrond, whose power was in wisdom.

greetings,
lathspell