Mecanim and triggers + playmaker + cameras (networking)

Hello,
I am new to unity advenced scripting, especialy triggers and i wonder if we can mix it with mecanim, can we produce this things :

1/ Allow players to select an object (an empty object placed above an object) if he near it (chair, sofa etc..) and choose an action, example "sit" "laydown" "jump" ect.. then the action animation will play in specific position (in front of the object selected for example)

2/ I have a scene with total of 6 cameras (including the main one) placed in the map, for now i just use F1 to F6 to switch from one to another, is there any solution to use trigger and if the player is entered a specific area, an F"x" camera will turn on ? (can we do this with playmker triggerIN, triggerEXIT and trigger Stay (something like that i cant really remember) ?

3/ Does triggers affect other players in multiplayer mode ? for example, if i press F5, the 5th camera will be changed in all players window or only the current player ? the cameras use LookAt(target) should i change target variable to something that network will undrestand ?

4/ Finaly is there simple to undrestand script that allow 2 players to exchange what is on their inventory ? it can be for free or for credits but in both cases it should be an inbput that will allow to pu 0 or other number


I know that i asked alot, but i think that making 1 thread and post the questions that i have is better than create new one for each one
I am trying to make a small virtual world where there is no combats but alot of interactions thats why these informations is a must for my project.

Thanks so much in advance !