I am getting somewhere with this order of operations
Open STL file in Inventor (make sure Mesh Enabler is installed and set up as an add in)
Right click on mesh feature in the tree
Convert to base
Select base (not face) and click ok
Export file as STEP
Open STEP file in Solidworks
Run Feature Recognition, turning off features that the part doesnt have to speed it up.
Have a part going through feature recognition now. Hopefully it works or gets close enough to be good in an assembly.