you'd know ISO extraction would work, I doubt the mold could live after being doused in 70+% ISO alcohol (I personally use 99% isopropanol). however, ISO is a dirty way of extraction, it's very hard to eliminate the alcohol completely in the final product. I doubt butane would really kill the mold, but I'd bet it would freeze it, which could help slow the spores from growing in your oil (could likely kill alot of them in the process as well).

I'd suppose it would depend on how you plan to extract the hash. that is a very good question however, being as I soon plan to make hash out of ounces (I should say POUNDS!) of shake I have laying around here, which I'm sure contains some mold (since I too usually try to cut it all out before smoking, noone wants to be smoking visible amounts of mold).