Hi missy,
In reply to question 1......its perfectly normal for cats/kittens to play with eachother and for some 'shouting' etc going on.
Mine do exactly the same when playing but one always gives up and walks away - only after a little hissing and meowing though!
And question 4........i often worry about this as my kitties have very sad faces lol! I dont think they are depressed though, i'd only start to worry if they went off their food, fell poorly or changed in any other way
