The air pump is now usuelss so you can take all of that out. Are you concerned at all about smog tests? If so you might want to hang on to that stuff. You can either get the air pump delete pulley, or take the air pump off and gut it the re-install, so that it acts just as an idler pulley.
I'm not sure about this. It seems to me that because of the location of the belt tensionner, you won't be able to put proper tension on the belt with the air pump pulley out of the picture. Someboddy who has done this hopefully can chime in, but I don't think it can be done that way. Look at the belt diagram, and you might see what I mean.