As title says. Many of you probably already knew it, but I just realized it and I haven't found it mentioned already in the sub.
This may or may not be common knowledge, but Tactic skills are not completely useless on a team with three of the same movement type. As long as the total number of a unit's movement type is less than three, the buff will activate, regardless of the number of other movement types.For example, my Arena team last week consisted of Nowi, B!Ike, V!Ike and Black Knight. Despite having three infantry on the team, Black Knight still received +6 DEF from DEF Tactic.