Best type of characters for Speed Primary/Secondary mods at level 77

So it really depends on who or what you want to do. For example in the Rex lead team you listed Rex is a character I would want high speed on so that he goes first and you can use the Tenacity up power before an enemy can attack and start placing debuffs. Some tanks like Baze you do not want speed on because you want them to wait a while before taking turns so that their taunt last longer.