I do agree that people who work for charities should be paid, but the overhead needs to be reasonable. I don't know where the line should be drawn, but if a charity has far worse overhead than average, that's probably a problem.
Many would say it doesn't matter if the end amount gets where it's supposed to, but humans don't like the concept of wasting their charity.
Case #3 looks more like your average Poverty Inc. Circle Jerk. Where the 2 million will be largely spent on hiring consultants for high premium.
Peacocks that invest energy into longer, heavier tails get more mates in the end, making it worth the investment for them and their offspring, but if all peacocks agreed to just halve the size of their tails, the species as a whole would suffer less predation and starvation (please ignore shoddy biology, take it as a crude analogy).
Raise 2 million with 25% going to advertising+execs => 1.5M for charity
Raise 10 million with 80% going to advertising and executives => 2M for charity
Which one is better? From the point of view of the people who need it the latter, so where do we draw the line? Can we draw any line?
IMHO doing something that helps others does not mean you have to do it for free unless it's done under false pretenses. There is probably an equilibrium for maximizing the money raised for the cause where advertising and execs expenses are NOT 0.
Note: totally made up numbers, it's just an example