Hi Picklepie
Nr. 1. The calculation to find the speed and the time is correct.
About the angle: When the ball lands it has the speed v. Written as a vector v = ( v->x , v->y) v->y means velocity in x direction.
To get the angle between floor and the velocity vector you have to calculate (v->y) / (v->x) = tan( angle). This you can easily see in a sketch.
If we solve this we get: inverse tan( (v->y) / (v->x) ) = angle
The question about the velocity: The velocity vector points at a certain time exactly in the direction where it is flying. So when the ball hits the floor, the ball is flying in the direction of its velocity vector at this moment. -> You take the final velocity to calculate the velocity vector.
Nr. 2. I think it's a perfectly elastic ball. This means: No loss of energy or velocity if something like a wall is hit.
First: I won't solve this for you, but give you a hint

The key of this exercise is to split the movement into a movement in x direction and one in y direction. Is the velocity in the y- direction affected by the bounce? And the velocity/movement in x- direction? If yes: How?
If it doesn't help just ask again.