Kameiras, iirc, are most some kind of amarrian variant of the Valklears. They are elite troops. Even more elite than the Valklear maybe, considering the indoctrination they get starting in their childhood. My bet is that they can surely be used as shocktroops when it is needed or to avoid too many casualties, but definitly not as meatshields, and rather as what were the SS in the WW2. Considering how the whole training of a single Kameira might cost, I highly doubt they are sent in the frontline to act as meatshields. For me it is kindof like the french legion (more elite though), they are sent in dirty places where nasty business has to be done to spare the regular troops, but they definitly are not second hand units either, quite the contrary.
I think that even if it is not specified in the PF (as much as I am aware of), the real amarrian meatshields troops are constituted of commoners or lesser bloodlines engaged in the navy/army. But somehow, most PF is centered around elite amarrian ground units, from cyberknights to kameiras, and elite counter boarding teams (and even the Dust soldiers in Templar One). We lack of info on their regular troops, but maybe the Amarr Empire actually does not use that many troops and heavily counts on elite units. Or maybe not.