Youd have a better chance of it all working if you started them all at 1.5-2 inches instead.
A 4-4.5 inch salvini is a bossy little thing compared to the rest...and can be quite violent. If you can, get the salvini smaller and you should be ok...unless, like the previous poster said, you get a mean jag. Then you might have problems...Id say the chances arent to high of that happening though, going from my experience. Ive had at least 8 and have had to re-home all but 1 of them because they were too passive/timid to defend themselves in my tanks with other cichlids. I never grew them larger than 8 inches though and it can change past that point.