The WMS may be 3" narrower but the spring pads are only 1/2" off. None of that stuff should really make or break whether you are going to use this axle. You can always use different backspacing on the wheels or get wheel spacers.
The Dodge does have external hubs which aren't as good as the Ford/Chevy internal style. The external hubs (which are all drive flanges, IIRC) have a habit of getting loose and exploding, plus there are no 35 spline options for them (lockouts or drive flanges).
The Chevy is probably a better front end to have but if you think you are going to take a hit selling this one and finding a Chevy one, just keep it.