That doesn't make a ton of sense to me. Seems like picking the mechanic first and then trying to find a character to fit it.
If anything, it makes more sense for Dagger to be the primary fighter and have Cloak pop in from nowhere for things like a teleport movement ability, super attacks that involve both characters, and maybe as part of her guard animation. Having him be some kind of summonable fighter a la the Stands doesn't really work well for me.
Niitsuma is an odd one, because while he and his team came up with some great, out-there gameplay twists for some characters, and made PHOENIX WRIGHT work, he turns right around and can't figure out how to make Blade play mechanically different from Deadpool or Dante. His thought process doesn't always make sense.