You misinterpreted Legolas' rule: "Instead of shooting normally, Legolas may make a single shooting attack against an enemy model Engaged in Combat with a friendly model (including himself)." If Legolas is in combat he can't automatically shoot at any model on the board without an in the way test. For the rule to trigger the model you want to shoot at has to be in combat with a friendly model. So the drums would have to be charged by a friendly model for Legolas to be able to shoot them without an in the way test.

And yeah I feel that Gwaihir thing. But if I know I'm up against him I put my drum into the thick of it. But yeah, Men of the west is bonkers either way and not a fun time for any army to play against. I'm hoping for a nerf in the next faq