The examples I have heard of that people are most worried about are things like preferred asteroid placements, opening maneuvers, engagement lanes and such. The rationale is that people might take notes on how an opponent approaches the game, and then pass that information onto another player. I know that I will verbally discuss how a game went with my friends (he ran with Obi here, when I was expecting a turn in) and such, but the idea is that specific turn-by-turn notes could give someone a leg up in the next match against them.

You are 100% allowed to have your opponent's list in front of you. Most events require a player submit their list to TT.to where all players can see it at their convenience. I also always bring multiple copies of my list (usually 1 per planned round and 2-3 extras) so that my opponent not only can have a copy for the match, but can keep it to reference later. The ships, upgrades and points of a list are all open information. How can a player play the game to his/her full ability level if he/she doesn't have access to such knowledge?

You can fail bomb/mine drops and it is explicitly laid out in the rules reference that if a bomb/mine has any portion of it outside the play area, the charge is regenerated and the token is removed as if the drop had never happened. I assume that with still hold true with thermal detonators for consistency reasons.