It should be hyphenated.
Yes, end-product is hyphenated. It is a noun and treated as one word which is hyphenated.
No.
Probably not.
The noun phrase 'four week vacation' does not need to be hyphenated.
Yes, one-on-one is hyphenated. I don't know why, exactly. It just is.
Yes and no. The out-of-plumb wall should be hyphenated while the wall was out of plumb should not.
group discussion
No
Point of sale is a business term used to describe when the retail transaction is complete. The phrase "point of sale" is not hyphenated.
yes
The second word should not be capitalized