By "Your only option would be to turn off value resetting within CB Conditional plugin parameters" what do you mean exactly?

Within CB Conditional > Parameters you can turn off value resetting. Value resetting resets the value of the field if the condition doesn't match then triggers conditions to allow chaining fields together.

Is there any way to hide the apprentice field if any one of the other 4 checkboxes are checked and if the apprentice field is checked to hide the other 4 fields?

You're creating a loop by doing this so no not really. The only way to stop the loop is to turn off value resetting. It seams like your condition maybe backwards though. You should have something like the following.

cb_apprentice - no conditions
cb_coordinator - show if cb_apprentice is not equal to 1

The above would work fine. Your Apprentice field would just always be available and if checked then your Coordinator field hides otherwise Coordinator shows fine.

Is there any way to add a CSS class to a CB field when it is set and remove a class from the field when it is unset. So, when cb_apprentice is ticked it will get a class added to the div around the checkbox and label and when it is unchecked the class gets removed?

From CB Conditional, no. You'd have to write the jQuery to do that your self.