If you don't need the offhand slot when they're respawing you could add a cust model to that slot and make the Fps size of the model cover the entire screen (although I don't know if it can be that big).
Im not sure what you mean.
But what I have right now suits the overall effect pretty nice. Clear + Invisibility
Are the sounds from a resource pack? Sounds great.
A custom Resource Pack that will go along with the map. Each map will have its own dedicated Resource Pack.
Sounds are legit game sounds, I didn't make them, just edited them. The piston sounds amazing.