As a team most likely to be affected by this, I'm comfortable with anything, including no punishment... but its also an isse for potential wild card teams.
As an alternative to the draconian post season ban (although fair, considering not the inadvertent illegal use of players itself, but rather the many days including call outs and PMs in the thread which led to further inaction, that is my main gripe personally), perhaps there could be a "docking" of some amount of wins. For example, when was Tobias first called out on this, when was he called out in PM or with his handle
@TobiasFunke in the thread, sorta of a formal you are on notice? How many games were these players involved after it was brought to his attention? Maybe it's 2, 5 I dont know...
Regardless, if we can find that moment and determine how many games the guys were used, maybe we say that if TF wins the division or a WC by more than that number of games, he is eligible. If he is say up by 2 games and we determine his penalty to be 4, then he misses. If he is up by 5 games and the penalty is four, he is still eligible.
I'm fine either way, but considering that it seems inadvertent a full post season ban may be too much, but considering TF was terribly irresponsible considering the public call outs and attempts to get his attention, something of significance does seem fair and in order.