Usually around the north country area we use Pressure treated wood for wall panels made of "Durarock" or cement board. The same type stuff you use in a shower tile area.Then you can if you want wire mesh it and cover with a scratch coat of mortar or stucco if you do not want seams to show.
We would just leave the seams to show and skim the panel with some cement and paint. They skirts always seam to move in some way so covering the seams does not always work out.
Leave an access to underneath and remove any organic soil from underneath. Another good idea is to cover the entire area under neath with plastic draining away from the foundations.
Good luck and wear your bump cap.