First Answer
Repeat framing for question 1
What are your side’s chances in a diamond contract? A great hand for partner would include the Ace-King of diamonds and King-Queen of clubs; most such hands would be sufficient for you to take ten tricks, and that’s only twelve HCP. On the other hand, partner could have 4=4=2=3 shape with lots of wasted values in the majors. So it’s not clear. That said, we would expect to take nine tricks in a diamond contract more often than not.
If you bid two notrump, and partner rebids three clubs, will you sign off in three diamonds? Definitely.
If you bid two notrump, and partner rebids three diamonds, will you pass? It wouldn’t be ridiculous to invite game with four diamonds, but with major suit strength sitting behind partner, we would pass three diamonds at matchpoints.
What’s your call?