South should open 2NT. Too strong for 1♦ , too weak for 2♣ and too few tricks for 2♦ .

North is in a quandary. Missing the ♣ A K means no slam may be on even if partner has 21 points. With five Spades you'd like to discover if you had a Spade fit but even if you find one then Blackwood won't help you unless partner has all three Aces. If you have a Spade fit you want it played by South if South doesn't have the ♣ A to avoid the risk of a lead through the ♣ K.

The use of a quantitative 4NT saying bid 6NT with 22 points else pass is quite attractive here. It missed the chance for finding a Spade fit but it avoids the risk of seeing a slam defeated by opponent's cashing two immediate Club tricks. 

An alternate sequence if you are playing transfers is to start 2NT - 3♥ - 3♠ -  3NT then going to 5♠ if partner bids four.

If you end up playing in Spades you must lead a low Spade from North in order to make 11 tricks.

When North overcalls East does better to force with 2♣ than immediately support Hearts. South bids to the level of the fit with three card Spade support but this doesn't put East West finding game in Hearts.

North leads ♠ K. West has a Spade loser, a Heart loser (if Hearts don't split 2-2) and a Diamond loser. It looks like the contract is safe but this pairs and overtricks matter. Can you see a good plan to make an extra trick?