When preparing an image for the web (or other media), the last two steps is usually to resize the image to the desired resolution and sharpen it at that resolution. However, when working in a larger/different color space than the final result is going to be exported in, when should I convert to the target color space relative to these two operations?
My last steps, in order, are resize, sharpen, convert color space from ProRGB to sRGB, convert to 8-bit.
The only really critical orders are sharpening after resizing and changing to 8-bit after changing the color space.
In fact, I was curious, so I just tried. One copy, I did my above steps. On the other copy, I converted color space, converted to 8-bit and then resized and sharpend. I put the images over each other and changed the blending mode to difference.
There was absolutely no pixel level difference between the two. I expect to see a few minor differences at 100% that would never show up on the print, but in the case of this one particular photo, there were absolutely no differences at all.
It doesn't really matter to be honest.
Whether you sharpen in Adobe RGB or sRGB for example will give you pretty much the same output.
Although as a general rule, I would recommend doing a colour space conversion as the last step in the editing process because this generally involves going to a smaller colour space which risks a loss of highlights and shadows as well as gradients in the image.