The best thing I read about informations on Erdnase was David Britland and Gazzo's "Phantoms of the Card Table". It contains an entire chapter dedicated to the mystery of Erdnase, all details found on him through years are mentioned in it; at least, there are a lot. Moreover I think TeeDee had read it too, beacause many of things he said are said in. And I approve him on all his claims.
Concerning my personnal opinion on Erdnase, I think he was actually a card cheat. Who has written his book for make advance the art of card manipulation, no matter that was in card magic or card cheating, that's the reader who make this choice.