As a side note, something I noticed seems to be unmentioned on this version of the evolutionist that I vaguely recall having been explicitly stated previously (likely on an older version though I may have been imagining things). Would be the issue of how mutations that need to be applied to specific things interact with the limit on how many times a given mutation may be taken. For example, if the evolutionist has two natural attacks and an elemental resistance, would it be able to have it twice on each natural attack at level 4, or would the limit on once per 2 levels apply across all natural attack it would be applied to? At present, it would seem to be the latter, though I could see arguments made for the former.
I also noticed there are some typos in the "Changing sizes and you" sidebar, specifically in the form of some missing 't's.