Can anyone provide basic comparison between abilities of these 3 technologies?

Specifically deinterlacing, scaling, noise clean up, overall picture quality across:
480i, 1080i specifically but images in general.

How much does Component versus HDMI impact the comparison?

You are comparing apples to oranges to banana's. Pixelworks and Faroudja are companies. Reon is a chipset offered by Silicon Optix that is featured in many mid level display and DVD devices.

What are you looking for exactly? An external processor or a display piece that features one of these companies?

Your best bet for these kind of questions is in the Video Processors forum.