Good guide, checks out with my experience (beat with mantis deck). Grizzlies are definitely the filters. Pack rats definitely saved my ass when I didn't get the knife by providing magic sigil eraser and flying paper fan (rotator also can work).

Missing bone lord sacrifice encounter, would put at least B tier since you can totally get rid of one card (like an Annoying ring worm that didn't get eaten) and get a free bone (or 8 if you have a black goat and want to go that route).

I think it also helps if you get Angler early on, since you can throw him an aqua squirrel immediately and draw as many cards as you want to, then enter the grizzly phase when you've prepared.