For each hand I had shown expected bidding and added some notes.

Many with the South hand would go straight to 4S.  That would indicates a week hand.  I think this is too strong.  Partner had not limited their hand.

There is a conventional bid we had not done yet that would take care of this situation.  It is a Jacoby 2NT if you would like to look it up.

This hand makes a Slam.  Again this is a hand where the Jacoby 2NT would help you bid beyond game.

South passes.  Don't save your partner.  They are able to make 3 S.

West may "Balance" in this hand over a 1 S bid with 2H.  (We will discuss this in Overcalls.)

North would then pass.  They have a big hand but partner has shown 0.

East would pass and the play would be 2 H.

Basic Staymen bidding

2C - Could you have a 4 card Major

2D - Don't have one

2 NT 8-9 HCP

3 NT With 17 enough for game.

1 D Opening Bid?

Should East overcall.  Only thought would be to lead directing but I would not do it since they don't have an A.  With the A would be a good bid.  An Overcall also tells the Declarer where the points are.

South bids 2 Spades.

North bids 3 Spades.

South knows N had 4 so together they have 10.  Bid 4S.