9ball,
New guys at the levels you mentioned are sent to the line and eventually released for their first revenue duties as F/Os with the same basic 'level' of credential; they are safe to operate the aircraft. Meaning, initial safety requirements met. Who determines this? The equipment chief pilot in their final checks.
As PIC, it is well within my personal capacity to 'assist' these very new and 'raw' first officers to get their hours going. Yes, a lot of Captains would frown on the thought that they have a greenhorn strapped on the right seat during an IMC approach into somewhere. In some occasions, I have felt that way. But that is what the job calls for, being PIC, as you know yourself. If the greenhorn is not improving as his hours grow, he is provided some form of remedial or even corrective training. Being part of flight operations entails having a lot of confidence in the Instructors, check pilots, admins, etc... to train and sign off these right seat hopefuls. The people responsible for pairing crews in flights does a fairly decent job of knowing who needs to fly where and who doesn't. Yes, I will accept either credential as is. And determine later (and recommend if necessary) if his or her performance justifies continuance of his revenue duties, or otherwise.
In 5J, there is check and balance.
good day to all!