I consider any being who removes their Soul and places it into another Object for the purpose of achieving Immortality to be a Lich. The Skeletonation is a Side Effect/Consequence of that, not a Requirement, and depending on the Media doesn't even really apply. I would consider Oldy Voldy a Lich after all, albeit a lame and boring one.
@ miyako19: But the Brimhats didn't turn Coco's mother to Stone, Coco did. And it's not like the Petrification one was the first Glyph in the book, Coco busted out over a Dozen Glyphs before she got to that one. So far the only time a Brimhat has directly and intentionally caused harm to another person is just recently, when they tried to drown Qifrey because he was trying to track them down. Combine that with the fundamentally flawed idea behind the Wizards Secrecy and yeah, Team Brimhat FTW.
Also in checking back over chapter 1 I like that Qifrey actually directly states that he needs to erase Coco's memory, indicating he knows how to do that and establishing that he can do this long before he does it to poor old gramps. Combined with the fact that Cowboy Cop from the Bridge/River Episode obviously new Qifrey , and I'm guessing he was once an Enforcer himself, but either quit or got fired after some sort of Incident, probably related to whatever the Brimhats ""Took"" from him.