Hi James,
I did look him up on wikipedia. The German version of the page has more information about him than the English one, but I do not speak German so I am relying on google translate. There is also a German wikipedia page for Josef Lasser von Zollheim, the second signature on the last page below the signature of Franz Joseph I.
I think the two things that I would like to know is (1) how you know whether this is the real thing or just an elaborate copy/hoax and (2) how rare or unusual these diplomas are. I located a person last night who may be a decendent of Heinrich Carl von Haymerle and I've emailed him to see whether he is. He may be able to shed more light on how this diploma ended up in the middle of the northern United States.
Hans