Evans, Cotton and Marsh were offered later. August, November, January. Sterup could (and should) still get his.
Also, why do we assume that he's still growing? I haven't seen many individuals reach 6'9" and then after they are 18 hit a "growth spurt". Considering he's already 3-4 inchces taller than his
brother's rivals 2008 height, I'd say he should be about done. His brother didn't grow at all after HS - his Northwest Missouri State bio still has him at 6'6"
here.
Also, as I've said before - everything basketball has him at 6'10" like this
piece. Basketball rosters tend to stretch the height - so he's probably 6'8 or 6'9.