Blending photos info please

When using the blending of two photo's technique instead of using a filer to recive a properly exposed shot would one run their anti noise software before or after blending is done? Or both? Would the same apply if I was blending two different images just for the special effect, say a shot of a telescope and a shot of the moon for instance. Thanks in advance.

I'm guessing that you're talking about this sort of blending?
https://photography-on-the.net/forum/showthre​ad.php?t=39702
I'd suggest that you wait to sharpen as the very last step in the process if you must. I don't sharpen at all on the main file that I save. Then, when I know if I'm making a pic for the web, or print, I'll resize & then sharpen, usually a different amount for each use.

I use Neat Image to remove noise from my photos. In my opinion, it's best to run Neat Image on unprocessed photos (i.e., before you do the blending). Neat Image uses noise profiles to determine the characteristics of the noise. If you use pre-made profiles (for a specific camera at a specific ISO setting), they will work best on unprocessed images. If you process the image, the noise will change too and it will most likely correspond less to the profile and will be harder to filter out.

I do sharpening always as the very last step before printing.