Hello I will help you with your question,
No the evap does not have to be removed to remove the expansion valve.
Discharge the system by recovering the refrigerant into an AC machine then remove the center bolt of the hoses at the firewall. Then remove the two allen headed screws from the valve and pull it off. Unless the valve is clogged there is little to break with this valve and it has a very good track record.
The steel allen bolts will sieze in the aluminum block so use good fitting tools and put moderate pressure on the bolts.
let me know what I can do to help you with this