How to use plugins with several themes
Each our plugin supports MultiThemes.
This example for NopSimpleCheckout.
Open plugin folder, open View subfolder, copy file from the folder SimpleCheckout what you want to change.
Where will plugin look at .cshtml files?
5. restart your store.
You can copy changed .cshtml file in one of the folder.
Don't forget to create subfolder SimpleCheckout.
For another plugins you should create subfolder with another name.