Does the crew of a steg have to throw their javelins at the same target that you fire the Giant Bow or Giant Blowguns at, or can they fire at closer targets while the higher range weapons target further away? Under the assumption it's 'one unit' then there is not split firing allowed, unless I am mistaken. I can't seem to find any other single unit in WHFB that has multiple ranged distances except the Steam Tank, and I am not even sure if that can split fire (cannon, steam gun, and driver's handgun). Thanks in advance!
We (locally) always play that the Skinks riding the Stegadon can throw their javelins at a different target. I do not believe you'll find a single reference to this in the Shooting section of the BRB. In Close Combat a model with more than one attack can divide its attacks between different targets. Shooting says nominate a unit to fire on one enemy unit, however. It's rather obvious that the ranges are different for the skinks vs. the howdah and each get a separate entry in the Stegadon's page and they go off at different times in the shooting phase and the FAQ states that the Great Bow cannot use a characters BS, so I figure it is at least intended to work that they can fire separately. In fact, you could also point to the fact that in challenges the character and mount fight as one but the skink crew are (again) treated as a separate entity. Is it how it is supposed to be? Beats me. I don't play tournaments.