I've no experience with turtles but according to this
http://www.monsterfishkeepers.com/forums/threads/stumped-cichlids-vanishing.659391/ snappers should have no tank mates.
SA cichlids should be ok with a pacu, in general. I'd say problems are unlikely but in our hobby one has to remember that such combinations of fish of varying aggression level are always a gamble.
We can only speak of trends or averages / expectations but individual cases do vary from total success to total disaster. Too many variables. Aggression is a subject to tank size, tank mate size, fish gender, fish age, water parameters, temp, pH, furniture, current, lighting, diet, etc. You change one of these things and all of a sudden, the situation changes too, for better, or for worse.