Front clearance appears to be dictated by the decision to use a lugged crown on the fork. Builder used on the of the commercially available crowns (because casting a custom one would be prohibitively expensive) The vertical clearance could be related to having an axle-to-crown that works with the rest of the geometry. Or to have the same axle-to-crown as "common" cyclocross forks so the owner can replace it if they want to.
As a side note, 32mm max strikes me as a rather odd size limitation. 33mm I could understand if the OP wants to stick to cyclocross tires -which mostly come in 33mm or less because UCI. Not that a millimeter will make a huge difference, is just an odd tire size limit to me.