I will try not to repeat what was already been said

2.Tai refer to BB as the standard measurement, I will just add that M is a more accurate measure since it takes into account the antes as well. Regarding your original question M does not neccessarily dictate how agressive you should be (except when short stacked) but which means you can apply this aggression with (i.e. raise/push/ call)
One thing you have to take into account with HoH is that it refers to tournaments that are usually deep stacked compared to standard online Sngs

5. There is no 'textbook' answer to playing the bubble, the key is agressiveness, but a lot has to do with stacks, reads etc...
best way is to post specific bubble hands and get comments on them

7. A few points about pot odds - one is that unless you are closing the action you cannot determine pot odds, you need to take assumptions on what people behind you will do, lets say you have an open ended str8 draw on the turn, so you have about 18% to make your hand, the pot is 5 way and you are 2nd to act, if 1st position bets even if the pot is giving you correct odds it is often correct to fold because someone behind you may raise, denying your pot odds.

Another thing that you have to learn are implied odds and reverse implied odds, since pot odds calc by itself is often not correct

last thing - if you are playing Sngs / MTTs, pot odds is still important but play a lesser role in your decision as compared to cash games, that it, there may be situations when it may be correct to call from pot odds point of view but incorrect to do so from the Sng point of view due to stack sizes