Problem A: 3NTBidding a major would be wrong. 3NT? Assuming, East has no more than 3 clubs west has no outside entry then we are likely to make 9 tricks in no trumps. Pass the double is an alternative but 3♣x-1 with 3NT= looks quite possible. So, I go for 3N.
Problem B: 4 This is so messy. Partner should be telling and not asking with his first re-bid. Nevertheless, I have to trust partner is doing the right thing. So, what have I got to tell partner? Pass is out because I have 11HCP, 6 more than I might have. Partner wants me to describe my hand and so passing now to catch up later could lead to misunderstandings and reproach. 3NT is out because I do not have a spade guard. So, the choice is between 4♣ and 4♦. I think it is more important to show that I have ♦ support rather than long clubs as at least 4♣s is implied. I am not happy and I do hope that partner is asking rather than telling for a very good reason. Let’s hope partner has something like: ♠xxx, ♥ AK, ♦ AQJxxx, ♣Ax and we roar into the ♦ slam. In fact could partner have anything less? It is very difficult to see less than a slam now. Perhaps ♠Jxx, ♥ KQ, ♦ AQJxxx, ♣Ax. That is 17 which could have been opened 1NT and was uprated with the very good 6 card ♦ suit. If we finish in 5♦ let us hope that the ♠ lead in 3NT with South declaring does not give us a ♠ stop and so 11 tricks in no trumps. Very unlikely.
Problem C: pass Give partner ♠ KJ10x, ♥ QJxx, ♦AKxx, x a well fitting 14 and it looks like we would make 4♠ and 3♣x would not go more than 1 off. OTOH give partner this fitting 13 HCP: ♠ Axxx, ♥Axxx, ♦ KQxx. ♣ x and we may not make even 3♠ and yet 3♣ is likely at least 1 off. I will narrowly go for pass.
Problem D: 2 2♠ on a doubleton is not ideal but better than bidding a minor because West is very likely to rebid 2♥ over a minor whereas might be shut up if I raise to 2♠.
Problem E: 5 4♦ by partner says you choose and surely a ♦ shortage. In the other 3 suits the remaining picture cards are ♠AJ, ♥QJ, ♣QJ = 11 points. So a small slam is almost certain and a grand if partner has a void in ♦s or A♦s. What do I find out if I bid 5♦? Blu’s analysis looks convincing but we would still miss a grand if partner has a ♦ void. I don’t think I have got a mechanism to find out if partner has a ♦ void so I will go with 5♦.
Problem F: yes/ 6 (F1) Do you agree with the double [BWS: cooperative-takeout]? (yes|no)
Yes given partner’s failure to make a support double ’s I echo what Blu said.
(F2) What call do you make?
4NT must be saying “choose a minor” so do I bid 5♦ or 6♦? Could partner have ♠x, ♥xxx, ♦AQJx, ♣AQJxx. Yes. Or could partner have ♠ x, ♥ Kxx, ♦ AQJx, ♣ QJ10xx? Yes perhaps. Or perhaps bid 3N here. This is a tough one. My gut feeling is that partner is more likely to have 2 aces than 1 ace when she bids 4NT. So I go for 6♦
Problem G: 3 Assume no Gazzilli so 3♠. The 7643 tail looks bad and partner with a singleton ♠ may be loth to bid 3N but all other bids are worse.
3♠.
Problem H: 7 I think with only 4 card suits it pays to be passive. So 7♠. Yes partner may well have ♠ Hxxx but likely would get it finessed anyway. Alternative is 10♣. The most I can expect is partner to have 4HCP. If partner has the J♣ or K♣ then I like a ♣ lead. OK if I lead a ♠ and declarer reels off 4♠ tricks I have to discard twice 4♥ and when I see dummy I will know which other. I fear being endplayed but to give away a trick on the lead would be worse.