Second Answer
Repeat framing for question 2
What’s your call? First consider what it means that partner did not bid. Probably partner would have bid with an unbalanced hand, so it’s likely that partner is balanced. Probably partner would have bid with significant extra values, so it’s likely that partner is minimum in high cards. Still, you might well make eight or perhaps nine tricks in notrump. But if partner has 11-13 HCP and is relatively balanced, surely we have a good chance to score plus 200 against two diamonds; East stands to be broke or nearly broke, so declarer likely will have a very unpleasant time declaring two diamonds. Also, you have help in any suit that partner might lead against two diamonds. So we favor passing.
The full deal appears on the next page.