got 2 quick questions, 1) we know that terradons can drop rocks on a turn they charge (if they fly over another unit) as per errata. if the terradons fly over a unit that is charged by something else can they still drop their rocks? the drop rocks happens in the remaining moves part of the movement phase and also teh errata tells us that it is treated as a shooting attack, both point towards the answer NO but i would like to be sure 2) slann has to take 1-4 disciplines nad those must be chosen when the army list is created, that much is clear. must they be declared during deployment? they aren't really magic items and they are chosen from the profile much like spears for saurus or javelins for skinks.
Not sure on the 1st question but would probably say no. On the Slann question i think they only need to be declared when used like magic items.
1) Never heard that question being asked actually... I am going to assume no since by the time the remaining moves happen, the unit is in combat. Logically they should be able to drop the rocks on the way to their combat target while the other unit is charging as well, but from a mechanical game perspective I don't think it would work. 2) This is more house rules and individual groups than anything. You obviously write his disciplines on your army list so you can't just pick whichever suits on turn 3 or whatever, but whether you exchange army lists before the battle is up to you and your opponent. If you don't switch lists (which is the more commonly accepted way and technically the rules, lots of casual groups do though) then you have no need to tell your opponent until one of them is activated, like magic items.