Sounds good bertoni, I was going to start one of this threads myself. Thanks!
So it's actually very simple, and you're making it more complicated than it needs to be. Firstly, I never said or in any way indicate that you need to know the exact amount of bacteria that needs to be grown in any sort of specific numbers. And why do we even need to know what specific number it is?
Fact is you don't need to know those numbers directly. All you have to do is to ensure that there are enough, and that's through simple tests, such as the 'dose ammonia to a certain point and see if it clears within 24 hours' or something similar (I prefer fish food, but that's me). That will test you whether you have enough bacteria to clear that much ammonia or fish food or whatever you are testing for, and that's all you need to know, whether you have enough bacteria or otherwise. Done. Simple. No need to get into complicated stuff like how many of each type of bacteria, or what composition of bacteria it is, or stuff like that.
Secondly, all you need to do is to identify the amount of food you are going to give, and that includes any sort of alternative regime that you may be aiming for. Granted, sometimes it is harder to estimate it than others, such as in the example you give. But it's not hard to give an approximate, and then tack on some extra. Like I keep on saying over and over, you're not attempting to grow a specific number of bacteria. You're growing an amount of bacteria, whatever that amount is, capable of taking care of a certain amount of organics.
So let's take that first example you gave. Say I will be giving the hippo tang, a yellow tang, an angel, a blenny, and two clowns a total of 100 pellets per day (just as an example), and the mandarin will hunt copepods all over, so let's imagine it as being a cube of brine shrimp. The snails and everything can consume a cube of food total. So a day, that'd be 100 pellets and two cubes. To be sure, I'd use say 125 pellets and 2.5 cubes to prepare the microbial population. Once the cycle is completed, I'd know then that the microbes in the tank can deal with that amount of food, and so feeding would be fine.
If you know you're going to feed different amounts each day, then simply go for the larger amount. I myself feed my fish anywhere between 2 to 6 times a day. So prepare the microbes to deal with 6 times a day feeding. If you end up only feeding twice a day, then that's still fine. If you do feed six times a day, then that's still fine. If you only feed once a day, but sometimes feed double the amount, then prepare the microbes to be able to deal with double the amount in one feed.
Whatever the amount of planned feeding, prepare the filtration system for that much.
As for algae eaters, same thing. How much grazing could they potentially do? Base it off that.
As for the specifics of each fish, this is where you have to research the needs of each fish. If some fish need to eat more than others, prepare for that. That's what research is for. Or worse case scenario, just prepare the microbes to handle a MUCH larger bioload than what you plan. And then you won't have to worry.
Conclusion:
-Plan ahead.
-Decide how much food is needed.
-If unsure, overestimate.
-Train the filtration system to deal with the maximum.
-Profit!