This a good match. I tend to favor Yamato but Haku has those Ice missors which is almost like instant teleportation. Haku could make a mirror appear behind yamato and attack from his blind side. However as people have said, Yamato is a well versed combatant and knows to watch his back and is an expert in binding. If Yamato gets trapped inside that dome of missors all he has to do is make a wooden barricade and haku cant do anything.
I would say Yamato would win.
On a side note: I think Kishi had to take yamato out of the war because the alliance would easily win with him. He could easily Bind all of the edo tensie's with wood and the sealing squad could seal them.