Did they ever publicly and officially declare how many of each fig were being distributed via the lottery mechanism? The discrepancy in numbers can be explained away several ways. So long as there was no official statement about the pool available. And no "I talked to some guy in the booth who told me how many they had" is not an official statement. It's not unheard of that they may have held back some number of their delivered production run to deal with unexpected situations. Things like defective product, or things used for internal marketing purposes (ie bribes to their corporate customers, vendors, etc. or the dreaded convention hall staff. ) the point is, if they never promised to deliver X number of items via the lottery mechanism, then guess what, these are promotional marketing materials, and they will decide which portions get used where to meet their marketing needs. Now if a portion of the figs were diverted in a way inconsistent with their plans or policies, then that is a matter for Lego to take up with their employees.
This is not to say that I like what they did here in any way. The management of the giveaway was rife with problems, and the concept behind these exclusive figures just shows that the Lego marketing group has little to no understanding of what their core superhero product is, or who or what their customer base is. Limiting ANY Superhero characters to a tiny give away at an limited attendance nerd fest is something that is guaranteed to piss of 99% of their SuperHero product fans. Recolors and weird variants are fine. But every character given away in such a limited manner must be in some way also available in at least some other form, to the more generalized customer base. This is what the fans of this product line expect. The characters are the reason they buy the products. Any time you tell them no or limit their access to the characters it hurts the business. There is no benefit to Lego to do these sorts of exclusive character giveaways. Only potential downsides.