It would be nice if the MP didn't just randomly choose a host - if you were guaranteed to be host, thereby choosing the game mode/game type you would at least have a chance of getting this list done before GTA V comes out. As it is, relying on getting into a game that you need to tick off (particularly when it comes down to the last half-dozen) could be a bloody nightmare.
All the MP achievements have to be done in ranked matches as far as I know... otherwise you could just set up games with your mates and let each other win. Oh the horror!