Bare aluminum wire can be attached to any screw terminal that is rated for aluminum wire. What that consists of specifically, I don't know. I don't seem to have any CO/ALR-rated devices around; all my spares look to be Cu-only.
Well, yes -- by the thickness of the wire. Big deal.
Of course it will; what are you talking about? Electricians do this all the time. A standard receptacle box is 2" wide, and a 120V receptacle with wires attached to screw terminals on each side is only about 1 3/8" outside dimension from screw head to screw head.
No, it doesn't.
Quite possibly it does protect two downstream *outlets*.
Just attach the wires to the screw terminals. It's easier and neater. [...]
Do yourself a favor and get a book or two on residential wiring from the library or from the Borg before you start.
I think I'd replace that outlet today -- and install the new one with pigtails.
It appears he may be right -- but it's not rocket science, either. You can learn nearly everything you need to know by reading, and by asking questions of those who know what they're doing. If you've ever followed other threads on the Wreck dealing with electrical wiring, you probably have a sense of whose advice you can trust [*], whose you should take with a grain of salt, and whose you should disregard altogether.
[*] I'd place LRod in that category, and, if I might be so immodest, myself. (I'm sure there are others here, too, and I don't mean to offend anyone whom I have inadvertently failed to mention.) People that LRod and I have disagreed with (or made sport of!) over electrical issues probably belong in one of the latter two categories.