What is "The Rumbelle War" on tumblr?

I think it's a big fan-fiction thing. At least, that's what the link blog and the Rumbelle War tracked tag indicate.

Also: both 'Rumpelle' and 'Rumbelle' are correct. They're both a combination of 'Rumpel' and 'Belle.' There really isn't an incorrect combination. Rumpelle, Rumbelle, Bellrump, Bellpel and every other combination of 'Belle' and 'Rumpelstiltskin' are correct as well.

Not sure. Maybe it's just that, the debate over their shipper name? I know there's been some talk over the ship name (I think one verison's spelling means something inappropriate I believe? Don't remember exactly.)

Sorry I can't be of más help.