Hi Jocelyn. The answer is Yes to your four questions.

P or not-P = (if not P, then not-P) and (if not not-P, then P) = tautology.

Given: (if P then P) then Q,
since: (if P then P) is true for all P,
therefore: Q.

Whence,
if Q is true, then [(P v not-P) implies Q] is true.
and
if Q is false, then [(P v not-P) implies Q] is false.

Notice that I use if-then statements rather than disjunctions (v), because the former are closer to natural thinking.

Just lay it all out. point by point.

Thank you, Avi.

If I do the truth table for some logic statement (such as [(P v not-P) implies Q] and I get all T's for the (P v not-P) part, that means the (p v not-p) part is a tautology, right?

But the whole thing [(P v not-P) implies Q] is not a tautology, right?

Is there a name for such a construction, besides "pointless"?

the (p v not-p) part is a tautology

the whole thing [(P v not-P) implies Q] is identical with Q - so it is a tautology of Q.

all this is indeed pointless,

but I guess it is intended as exercise. enjoy!

Thank you again, Avi.

Most kind of you.