You're mostly right. The 35mm will have an EFL of 52mm, just as your 50mm will have an EFL of 75mm. Everything gets multiplied by the 1.5x crop factor.
When "DX" is applied to the lens, it means that it's designed so that it only puts light onto an area the size of a DX sensor. That means that, if you put it on an FX (full-frame) sensor-bearing body, only portion of the photograph will have an actual picture on it; the rest will be dark.
In turn, many (all?) Nikon FX-based cameras have a "DX crop mode" where they shrink the size of the photo to avoid this. This effectively makes your camera a very expensive DX sensor, with the same crop factor/EFL/field of view.
Conversely, your 50mm non-DX lens is "wasting" light on a DX sensor. I don't think there's any real downside to this besides lens size/cost.
Don't let this influence you when deciding between these two lenses though. Think about what you're going to be shooting, and then perhaps cost. The 50mm is better for portraits; the 35mm will be better (IMO) for everything else due to its wider viewing angle. I find 35mm to be a good general-purpose length; 50mm often is too tight for anything but head shots. They're both fine lenses though.