Id say
if you want to keep them all, get the jag now. My experience with the parachromis species is if its brought in as the low fish on the totem pole, it tends to be less of a harasser or outright murderer.
If it were me, Id get the jag & carpintis (if I recall, thats what you were getting, not a TRUE texas), then when things get crowded, get rid of the O's & JDs & keep the jewels & carpintis and throw the convicts in (plus about 6-10 more cons). The jewels are quick enough to get away and the cons are ballsy enough to not be scared of the bigger fish. I think convicts as dithers works out WAY better than danios, tetras etc...plus cons are some cool *** fish, especially in large groups.
Youre BF sounds like my
EX GF!