I never understood how Aharon and his two sons were physically capable of being the only kohanim until more kohanim were born. They would've had to eat many, many tons of meat every day (all the kodshei kodashim) all by themselves. First they had to eat all the meat from all the Korbanos Tzibbus. Then, just imagine, every day approximately 1 in 10,000 people brought a Chatas or Asham. They're probably obligated to eat approximately 65 cows a day! I don't know how much meat cow has, but I know it's A LOT!!!
All three of them had to be awake all night guarding the Beis Hamikdash (Gemara Tamid 26a) so they had no time to sleep ever.
During the Beis Hamikdash when there were approximately 7 times as many Jews they needed thousands of kohanim and complicated procedures to bring all the korban pesachs in one day, how could the three of them have done it alone?
Many other things like this. I don't see how stuff like this could even been remotely possible.