Status update:

Did I do it? <a rel="nofollow" class="external text" href="https://www.reddit.com/r/fallenlondon/comments/16c8vlv/i_appear_to_have_popped_an_extraordinary_number/">Yes.</a>

What did it cost? 560 Echoes.

And no, neither popping 400 Weasels nor sacrificing 400 Weasels to the Boatman changed my Weaseller status. Which is a bummer.