Question two for my game ?

Please go to my other question, but there's a scene i'm still working on. (zombie game)

-- 1. How do I animate a character to do walking, like animations, so I can use for my scene.

--2. The zombie I will be making are two problems, how do I make them do walking, attack, and move to player in a certain radius near them and gunshots.

--3. How do I customize a zombie, like with certain objects on them, and still control their balance.

(SO I CAN MAKE LEAD PIPES IN THERE HEAD WITHOUT MAKING THEM FALL OVER)

and --4. How do I make an object fall, (anchored defaultly, then there's a block to step on to make it unanchor OR mouse click.) Please explain my problems in Lua wise