The most popular macro lenses for dSLRs are 60mm, 90mm, and 105mm. Of course, there are other focal lengths. I don't think I've ever seen a 24mm macro lens, unless we're talking micro 4/3 or some other non-35mm sensor size.
If you want to replicate the effect in the article, you'd be using a 24mm macro lens, yes. Mitakon makes multiple, and laowa makes multiple for all mounts.
I really don't think they are. The 24mm "probe" lens is pretty famous and widespread, and it's actually the #2 item for the query "macro lens" on Google shopping and it's the first macro lens you'll see on Google images. Beyond that, there's a whole plethora of ~24mm macro lenses and they're pretty dominant in the budget side of macro lenses nowadays.
