Can anyone add some context on the X, Y, Z beyond what I have below and how we might use Stewart? I'm seeing in places that Evan Stewart is listed as a Y receiver. Both Ainias and Moose go in the 195 range while Stewart is around 175 so I thought he'd more of a Z.

X - usually lines up on the line of scrimmage out wide, tends to be bigger and more physical
Z - slot receiver, lines up off the line and may split wide depending on formation
Y - similar to Z but lines up closer to the line more and may be asked to do more blocking

Z isn't a slot, it's your split end. Most coaches use H or F as the slot. Jimbo looks like he uses F when it's a receiver and T when it's another tight end. As for Evan Stewart Idk where Jimbo would want him. Anias will be starting as our slot this year, and Moose looks like the next man up. I don't see a particularly big roll for him this year unless he plays mostly outside.

Traditionally, here is how they were lined up:

X: split end out wide and on the line.
Y: tight end, opposite side of the X.
Z: split end out wide off the line, same side as the Y
H: like a Y, but off the line of scrimmage

Today, it looks like some got drunk and spilled alphabet soup. They're moved around to find mismatches. Its easier to put the Z and H in motion because of rules about who is on the line and who can go downfield.

They've also moved away from the slot receiver exclusively being the short quick possession receiver. Now they look for mismatches with tall receivers.