I am going to agree with alot of people on this one.

Non-Cav Ambush Units = High charge, moderate to high att, decent morale, and faster than most like the (6-12-13) units. These units would be Muwahid Foot Soldiers, Ghazi Infantry, Fanatics, Highland Clansmen, and Nizaris. Hashishin and some of the skirmishers, Although I have toturn of the fire at will on those or it blows the element of surprise. There are also Galloglasses and Woodsmen.

Cav Ambush Units = I prefer speedy with a High charge, like Steppe Cav, but will take slower with a high charge like Mounted Sarges.

I will also state I am not very good at staging ambushes to this day. I try, but more often than not, it ends up in failure.