Thinking about this in game terms, if you had a group of characters that all started out with the same race and the same attribute scores, just how different could they become as they advanced?
I'm of the opinion that a well designed base class allows a party of six characters to all play that same class, and yet each have a distinct shtick.
This is an even tighter constraint however, as how you've posed the question each of the characters cannot be differentiated by their ability schtick - ei "the smart one", "the strong one", "the tough one", etc.
However, realistically speaking, that's not true. Genetics between only indicate a propensity for certain abilities. Identical twins - which are natural clones - rarely end up being exactly identical in interests and abilities. I'd expect 14 identical persons to end up far from identical in anything but a movie. In fact, in game terms you could probably expect each adult twin to have ability scores in a small range (say +/-2) depending on neonatal development, childhood, and their interests. You don't develop intelligence fully without intellectual pursuits. You don't develop strength fully without athletic pursuits. And so forth. And as they advanced, obviously game systems will allow divergence in various ways as well. In D20 variants, by the time each is 8th level the divergence could be quite large (ability score change every 4 levels). In skill based systems this is even more true.
In D&D, supposing each of the clones favored intellectual ability, you could still end up with rogues, wizards, marshals, factotums, alchemists, etc. As they advanced you could end up with all sorts of different builds. Clones with different mothers raised apart would be pretty much completely different people. They probably would only vaguely look like each other.
Completely aside, the show sounds ridiculous. Is it a comedy? If not, what does an "anti-cloning religious sect" do about identical twins? What in the world would the proposed religious basis of this belief system be? I mean, why would you develop a religious aversion to cloning before it became a widespread practice, and if it became a widespread practice why would anyone be surprised to discover they were a clone? Why would a corporation create a product and then randomly distribute it all over the place? What in the world is the upside of cloning persons and then letting them roam around everywhere?
