No holes.. at all..
so 1) Yes he was pretending.. he needed to make everyone belive that he was madara because madara is fearsome beast and when everyone hear a name Uchiha Madara, they shit into their pants..
2) Imagine that you are waiting for something one-two-three years(I don't know how much did it pass but it doesn't matter).. of course that it would be long to wait.. you couldn't wait for month not to say years(same goes for me and everyone else).. if you don't get, I'll explain it better.. you want vengance, really badly.. and you have to wait.. Imagine that..(or you could imagine that you need to wait someone you love for 1-2-3 years..) I hope that you get it
as for kyuubi "you" part.. obito had spiral zetsu on him and madara surely gave some powers to obito(same as itachi gave to sasuke) so thats the reason why kyuubi recognized him..
3) I have two possible answers here.. first one is obvius.. genjutsu.. and second one i zetsu tranformed to madara.. I don't see why is this imposible..
4) It's NOT madara.. it only his will, not his mind or something.. it's like (on your 1st comment) when obito told to naruto that hashirama will is within naruto.. its not like hashirama is within naruto, only his will.. hope that you understand what I mean..
That's all folks