I really enjoyed this skip and it's relations to ww2, the holocaust, and the insurgency. My main criticisms would be a number of minor grammar errors (the last sentence of the first addendum for example), the overly long title for the containment history section, and the existence of the buchenwald hypothesis addendum. The latter is just an exposition dump, whose contents can be inferred already by any attentive reader. Ending the article on the instructions about finding insurgencey art is a much better end.
It's also never explained why exactly people exploring anomaly 3 are dosed with toxins? That seemed to come out of nowhere. Finally, instead of using anomaly type 1, 2, etc. you may want to use the more standard sub naming system if SCP-xxxx-A, -B, etc.