Aw, hey there Yi, you wanna play with the big boys? Isn't that cute.
Yorick hits him with W, AA, Qs to reset AA timer, E, Ult *if Yi hasn't been laning against Yorick, and thus got fed somehow*, dead Yi.
Jarvan has no excuse getting killed there. If he's low, ult Yi, then EQ out, otherwise just kill him.
Malphite should win, and if he isn't winning, should EASILY last long enough for his team mates to finish what they're doing, then B, maybe do dragon or something, and then come over to help.
Edit: Also, top lane or mid? Because a bit past half in mid is less than halfway in top.
If I'm Caitlyn and by myself, I'll assume I'm mid Cait for some reason, drop a trap behind me a little ways, and then net Yi to get most of the way back to my tower. He really shouldn't kill me fast enough for me not to be able to get away.