Thing is, I don't think the activity on RMS will be enough to have full fledge WoE's.
Also keep in mind that the test server is not supported by GM's and such, so if there should be an increase of players.. mixed with the things you mentioned (Organized WoE etc) it would need support. Which unfortunately isn't going to happen.. im afraid.
I suggest, if you want to have WoE on the test server.. you would have to organize it yourself, collect and search for players yourself and find a castle that is empty.
Also about the NPC suggestion.., err hmm. That's going to be a lot of trouble for a plan that might not work out the way you think it would.