What is your cell size relative to the feature size? This will be important because if you plan to determine slope SA's surface, slope), then I presume you will have a window of slopes that meet your criteria which you want to extract.
The elevation difference issue is a bit more complicated since there isn't a 'difference from', but you can determine elevation range within a neighborhood (SA's neighborhood functions).
The combination of matching slope (and aspect?) and elevation difference for your neighborhood size and shape might lead to a solution.
But... a picture of your situation might suggest whether manual digitizing would result in better or supportive results.
