It depends on the sizes of the balls. If the basket ball is size 4 and soccer ball is size 5 soccer ball could be bigger.
you hold the ball in what ever hand you are mostly using(left or right handed) and clench your fist while following through with the ball
well no you can't run around with it but you are aloud one step (a power step) but you have to passe or shoot before your pivot foot leaves the ground!
a bsket ball bounces hightest then come a tennis ball and then a soccer ball
A strike ball has less padding and is used for training and a match ball is used for games and has more padding and better flight in the air.