I am wondering if anyone can list descriptions of what each of these Tools do so I can make sure my decisions are best for my needs & wants.
I’ve been searching the web for awhile now, but I mostly read comments about why & why not to install Avast, NOT descriptions on what each Tool actually does. I did find some information, but nothing complete.
Have you checked FAQ section? https://www.avast.com/en-eu/faq.php
Avast blog https://blog.avast.com/
Agreed it would be nice if there was information and description of every tool listed in the Custom Installation options right there; accessible by drop down or link…something.
As is, I think the Avast website and always your friend ‘Google’
Thanks for the links Pondus, helped a little. Found out I don’t need the Mail Shield after all. I might use Rescue Disk down the line & Browser Cleanup may come in handy, IF CCleaner lets me down … but it hasn’t in the past.
Ccleaner isn’t really designed to remove unwanted toolbars. 
That’s the main job of the Avast Browser Cleanup Tool.
(As with all cleanup tools, handle with care.)
You might also consider adding Unchecky to your protection to prevent getting unwanted add-ons in the first place.