LOL yeah, at just under 30mm it starts to go "Looney Toons" on you at the corners. At 18mm, it's just a bit. A hood even a third less this height would be fine.
So I just bought
this shorter version for 11 bux shipped and I think it will fit the bill nicely. Regardless, I don't usually shoot lower than 30mm-ish with the WR kit anyways, but pairing this second hood to it makes more sense.
My point is that grabbing a cheap Promaster branded hood is an easy way to rectify the missing hood issue for the kit lenses. I've confirmed they fit.