Shield+Grabbing, spot dodging, short-hop dodge all crucial components to beating the speedy types. Just be patient, evade their attacks, and wait for that opening.
If Shiek's camping just approach him with caution (dodge or shield his needles) but anticipate that at any moment he could go offensive and dash at you - be ready with a spot dodge and then proceed to jab at him.
And like Ussi said - your buddy should play Zelda versus Ike - Shiek is cake compared to Zelda. The hitbox on Zelda's UPsmash is ridiculous and Din's Fire is particularly annoying.