Four fateful decisions

[rod]

All vulnerable, playing IMPS, you, North pick up this hand and hear West open 1♣.

♠ J
♥ K103
♦ AKJ1076532
♣ --

Your call?

[rod]

All vulnerable, playing IMPS, you, South pick up this hand and hear West open 1♣ and partner overcall 5♦ with East passing.

♠ 732
♥ J98
♦ 984
♣ AKQ3

Your call? Does it matter if it's the last board and you think you need a swing?

[rod]

All vulnerable, playing IMPS, you, West pick up this hand and open 1♣. It then goes 5♦, pass, 6♦.

♠ AQ105
♥ AQ42
♦ --
♣ J10874

Do you double? What does a double mean in your partnership?

[rod]

All vulnerable, playing IMPS, you, East pick up this hand. Partner opens 1♣ and it then goes 5♦, pass, 6♦, all pass.

♠ K9864
♥ 765
♦ Q
♣ 9652

What do you lead? Does it matter if partner doubles instead of passing?

Discuss.