I can only advise regarding the longer formats as that is all I play.
As far as aggression is concerned, start at 4 until at batsmen reaches around 20 then reduce to 3. If he reaches 50 reduce to 2. You may have to go down to 1 or zero if he's on his way to a century or above. I pretty much always bowl middle and off, although will bowl outside off at times, especially if a batsman favours the legside or the ball is swinging.
Very rarely I will bowl more aggressively at 5, if say it's the second innings and we've got a huge lead. Sometimes this works, sometimes not.
Regarding length, generally on a good length, sometimes full if the ball is swinging. For example if it's cloudy I would go with one bowler hitting a good length and the other bowling full and adjust accordingly.
You started another thread about bowling short. This can be successful at times, I find it's probably best when a pitch has degraded and favouring the pace bowlers. Never bowl above 3 aggression with the default fields as there won't be enough deep fielders. I have found some success bowling short to batsmen who favour spin and prefer to play off the backfoot, similarly with the tailenders, as they will have a go which can lead to them throwing their wicket away.
Try things for a couple of overs, if it doesn't work go back to, good length/middle and off.
The default fields are fine although I often set my own. The above is only a rough guide and I will change things slightly depending on the match situation, conditions, form and performance.. It definitely helps to watch every ball to get an idea of what is happening.