No because that would deny arbiter from having his own actual costume. Plus I’m pretty sure the hit boxes wouldn’t line up well between the two models. Chief would have to be in a really awkward position with Alien shaped limbs.
I don’t think it’ll work for one MC has a completely different body shape than the Arbiter so they’ll either have to make another rig which would be no point might well just add MC or use the same rig which would look disturbing to say the least.
Or give an MC based accessory set for fulgore since one of his face masks looks like one of the titanfall soldiers helmets or at least to me anyway that way you’ll have a look alike costume instead of a new guest.
I’ve had this EXACT same idea for teh same EXACT reason.
It isn’t difficult to imagin at all imho. Halo 2 and Halo 3 did it. Spartans and Elites are similar enough. But we could also give Fulgore a really good Spartan costume too! Grunt humpback thing on Sabrewulf too!
It would be even easier to do with a Gears of War Locust/Marcus Phoenix character too.