Signus got an ambivalent go-ahead from Hutchins. (I think the message went along the lines of "I can't stop you", which is kinda depressing, but oh well.)
Ice e-mailed Hutchins a couple days ago to ask if MAT could riff .45 Caliber Angel, who gave the same response. When asked for a clear yes or no, he said yes. So it's fine, it's just that Hutchins personally is bored with the idea of MSTing fics. More or less. [shrug] One would assume the same principal applies to Hopelessly Lost.