While some of them could be fun (like the wooden mallet), I wouldn’t like for them to go to lengths similar to Soul Caliburs. And yeah, GW would likely be the biggest hurdle for it, even if they were only Illusions.
Personally, if something like them were implemented, something weapon-like but clearly improvised could work best, holding some of the seriousness of the setting while still appearing handicapped or even somewhat weird. Ranged weapons are harder to figure out (maybe something that looks like they were put together from scraps in three minutes), but melee weapons could be a lot of things: Branches for swords, cudgels for maces and hammers, a long, pointy stick for spear, a fire poker for Rapier… Things that aren’t blatantly silly, but still something you would only expect as a weapon of last resort. I think their effectiveness despite appearance would bring enough weirdness in (imagine using a big branch as an Exec Sword).