Pretty sure it works in Single player, the only difference is it should be even easier.
Also it's been awhile since I've tried on Foney, but I think Red Saber + Crimson Coat is slightly better then Clio? Not sure what the formula is for that; especially with the high grind though.
As For Hucast/Seal It's not as fun or fast but Drill Launcher is a cheap way to do it, there's probably a better way here I haven't thought of, I don't play Hunter anymore either.