Seeking Wisdom.

[Gaiteka]

A few basic details. I ref FIBA rules/mechanics, 2-man officiating.
I have had a few questions for a while and thought this would be the best place to seek answers.

1) My partner and I have a double whistle in a shared area. They are on lead and take the call. They call a block, but I clearly saw an offensive elbow come before the contact they have called. How should I go about bringing this to their attention in a way which A) Maintains the integrity of the game, B) Doesn't suggest to the players that we disagree and C) preserves the relationship between officials (i.e. i dont want it to seem like i dont trust them). Is it better sometimes to just bury it for the sake of the game?

2) I have noticed several referees, particularly those in the NBA do not utilise a lanyard, they just use the whistle by itself. Is this common? Do you know why they prefer this style? What are the advantages and disadvantages?

3) Are their any unofficial signals that you use to communicate in game? For example, a signal to say 'we need to tighten this game up' or 'watch (some player) off ball' etc?

4) Finally, somewhat related to question 1, how should I go about coaches questions when i believe the other official has made an incorrect call? For examples, when the other official has called an obvious charge as a block or made a bad travel call, and the coach tries to question me as to why it was called. I dont know if I should be supporting my fellow ref, or if i should be honest and say "i didnt see it, you will need to ask him".

All responses and insight is greatly welcomed. Thankyou