What if, in relation to the parts you can obtain in the Microbe stage there are tech trees relating to each one.
Points could be added to already selected parts to produce more effective and efficient parts but could also be removed and put into other parts based on necessity.
This is just in case for beyond microbe stage in which you may need to have a basis for the next adaptation. by this I mean to give an example of how snakes at one point in their evolution had legs but opted to move via their body muscles rather than the limbs they once had (not that they had a choice ^^’)
For Toxins alone you could spec them into giving certain effects such as paralysis, confusion or weakening/bleeding, later adaptations could modify the toxin to have multiple effects or have specific uses.
Was gonna draw this all out but wasn’t really worth it as it would just get over complicated.