if you use a 35mm lens in place of a 50mm with the intent to crop for the same FOV, you do get the same perspective, but you sacrifice the shallow DOF used to separate subject from the background.
Example 35mm vs 50mm in NikonD800, at 1.5meters distance (typical portrait setting): 50mm 1.4 gives 7cm DOF, while 35mm gives 15cm DOF.
That can be both good or bad, ofc.
I just wanted to make sure you know that you wont be making the same images with your "hack".
Secondly, a 16MP image resized from a 36MP image will be better quality, retaining more details, even if you sharpen the 16MP crop. You will see more textures from the resized 36MP image, and then sharpen that.
So you should only get the 35mm for wide angle usage.