Ok hand seals.
Every jutsu requires Hand seals.
Yes all.
It doesnt matter if they dont show a person doing all of them,They are still required. Its basic Narutoien sceince. You use handseals to release chakra and channel it.
Kage bushin requires more hand seals..its done some where but i know it does require more then the basic 1 cross he does.
The number of hand seals i BELEIVE reprosent the difficulity in the jutsu,as in the more complex outcome of the jutsu then the more hand seals...