CEL Communication Problem?

I am getting U011A, U010C, P245A error codes. The scanner I/M Monitor Status shows MIS, CAT, O2S and EGR as red (no communication). Sometimes, only CAT and EGR have no communication. I purchased this used truck. The seller told me a mechanic found the communication problem to be a loose connnection, fixed with zip tie (I do not see any). A previous owner also added Chev mirrors, which have turn signal indicators, puddle lights, and back up lights, and I do not know where and how he connected to the appropriate circuits. I removed the TIPM, everything externally looks good at pins and connectors, all cleaned with DeoxIT, dried and tested. Same problem.

#1, is it safe to run, or should it be parked until fixed, #2, you previously suggested a CAN tool to scan for communication issues between systems. Is this where I need to start? If I need to start with checking pins for communication, where would I go to figure out how to do it. I did copy your TIPM schematics from a prev post. # 3, I can solder and wire, so I should be able to make easy repairs.

Thanks,
Rich