Editorial license means that customer can't use obtained product commercially. Usually you want to sell your models under editorial use license, if your model is partially covered by copyrighted material and you didn't acquired rights to use it. For example, if you created existing in real world car model, you can't legally sell it under regular royalty free license. in fact, even selling it under editorial license is a bit of a grey area, but it's common practice in 3d model stock market, so you should be ok with that.
As for the second question, no, you can't sell models that aren't yours - that's calling piracy and is punished by law.