Answer:
I like this to be natural. There are some hands with length in the opponent’s suit which do not warrant a risky penalty pass, especially sitting under the bidder. My rule is when a hand that has opened or overcalled 1NT naturally then bids 2NT after a take-out double, that is natural. His partner’s action, by contrast, would be two-suited in a parallel sequence.

Answer: I tend to double with any hand which I would open if it has the appropriate shape – such as a perfect 4-4-4-1, 5-4-3-1 or 5-4-4-0 shape, I will double with less, but if it is imperfect, say a 4-4-3-2 with three in the enemy suit, or 4-3-3-3, I need  more than an opening bid. Additionally, you need a little more for a double of one spade, forcing to the two-level if you have a fit, than doubles of other one-level openings.

Answer: Pass
I would pass for penalty holding two trump tricks, and lead the ♠10 to try and work a ruff for another. 3♣ is very likely to go down and the penalty could well be very profitable for my side. Additionally, we might not have enough for game.

Answer: No. I only open light at the one-level in third seat with good reason, namely a suit that I am keen for my partner to lead, or with some shape in an attempt to disrupt the enemy auction. A one-diamond opening is apt to do little on that front, and partner’s suit was nothing to write home about. His opening was ill-disciplined.

Answer:
First, this is only a problem if their partner has a subsequent decision. If that is so, best is to agree, at the end of the bidding, that there was a break in tempo. You can then call the director after the hand if you think you have been damaged. Of course, you can also call the director after the auction if you like. You should try not to be aggressive or imply misconduct has taken place. For all you know, the partner of the hesitator might have bid reasonably; if not, the director can sort it out later.