In case some one ever runs a crossed this having the same issue…
I put the multiple serial sketch from the Arduino examples on the ArduPilot Mega and everything seems to work fine now. (and the way i thought 3 serial devices tied together would)
I guess the pins on the microprocessor were initializing to a low resistance state that did not allow for serial communication. This accounts for the odd 3.3 and 5V behavior and for the momentary data after and during resets.