So the EZ start turns over the motor, but the glow plug doesn't ignite. Then you put a glow plug igniter on there, turn over motor with EZ start, and it fires?

There's a short in your easy start wiring. You can get another one for about $5 at the hobby store or just check the wire going from the glow plug back to the EZ start, may be cut somewhere, just splice it to fix.