Well long term you may have problems, in that most peacock bass will grow large enough to eat a female jack Dempsey. The cichla will also grow much faster, and a male JD may be outgrown and eaten as well. Beyond that, the jack dempseys are usually more boisterous at a small size and may bully the peacocks before they are outgrown. Also, cichla prefer softer water with a lower pH, wheras jack dempseys like the opposite. Cichla will also require a 200+ gallon aquarium eventually, due to their huge size.
In my opinion, not the greatest combo long term. May work out in the short term if your JD can grow quickly enough to avoid being eaten.