I wouldn't re-arrange decor...unless you really know your fish and know what your doing. In general, mbuna establish themselves quicker then any other fish will. Been mixing the 2 for over 3 decades now, so i have seen countless of times, how mbuna establish themselves quick, in comparison to most new worlds ( when they are first introduced, or when decor is re-arranged). For example, some fish such as an auratus, depending on the particular tankmates and circumstances.....HAS to be temporarily removed from the tank, if you re-arrange decor, because of it's nasty demeanor and the fact that it is very likely to take advantage of it's ability to re-establish much quicker then most of it's tankmates.
At 5-6", though sexually mature, your Jags are still very young. Still small and undeveloped. You really can't judge too much what the species is really like, nor what your fishes will become. Of course every individual fish is different as well. Even amongst CA cichlids, jags are often not the most dominant fish at this size and age. Sometimes, but often not.
Mbuna, ounce for ounce, are generally very capable fish. They have high-energy aggression. Often, it takes some time for CA cichlids to learn how to defend against the mbuna style and ability. Looking on the positive side: probably a good thing that somebody in your tank can defend against the jags; otherwise they might take over your whole tank and possibly kill the other inhabitants.