re: scent block underwear or camo. Is it worth it?

It helps to a degree.
The newer styles that help eliminate /reduce bacteria are probably a better deal if they do what they say. Bacteria on the skin is what causes human scent". ScentLok claims it absorbs this odor, and when new I believe it does to a degree. However a class action lawsuit by hunters/chemists proved that their products cannot be "rejuvenated " at normal dryer temps as claimed. But I do think they help, as do the silver lined suits.
Now none of this helps if you don't take care of the rest of your gear, but it sounds like you do.
Also I would lose the scent wafers. Nothing will cover up the human scent to a whitetail. So to a mature buck instead of smelling like a human, you will just smell like a human with Earth scented wafers.
You can't kill human scent with these miracle products. However you can reduce your scent significantly. As a bowhunter this is much more important than to a rifle hunter. With these products, and a good regime of scent free clothes, rubber boots and clean gear you effectively reduce your scent and thus decrease the range at which a whitetail will detect you downwind. Of course you should always use wind direction to your advantage, but if it does momentarily swirl or if big boy circles you downwind (which they very often do) he won't pick you up until he's in bow range or thereabouts, as opposed to whiffing your scent 150 yards away and you never even getting the chance to draw on him.
Just my two scents.......