electrical damage due to loose battery cables

Wondering if anyone might know if it is possible to damage a host of electrical components on the truck when battery cables are not connected tight. I had my 3/4 ton diesel truck in the shop for tune-up and replacement of main fuel pump and the shop did not re-tighten the battery cables sufficiently. AFter the main fuel pump was replaced I noticed that the truck began stalling frequently and discovered that the cables were not tight. I tightened the cables and returned the truck to the shop.

The shop replaced the module on the injector pump and truck seems to run ok now except I'm now getting injector pump stepper motor error codes. Before taking the truck in I had NEVER gotten any error codes of any kind.

So, since getting the truck back I have noticed that 1) the fuel gauge bounces all over, 2) the module on the fuel injector pump had to be replaced (as I mentioned above), 3) I am now getting error codes for the fuel injector pump stepper motor (never had an error before taking truck to shop) and 4) front axel thermal actuator seems to be dead.

Could all these be related? I know the owner's manual warns about disconnecting the battery with the ignition on...