There isn't an autoresponder for editor applications. All applications are evaluated by meta editors. If an application is horrible with poor spelling, miscapitalizations and obvious bias towards a site that the applicant is affiliated with, those applications are trashed fairly quickly.
Difficult to say. The list of applicants is quite huge, but most applications are dealt with within a few days. It also depends on the category you applied for, but generally it takes less than 1 month.