A breeding pair of festae with others isn't the best idea but it can be done.Comes down to the individuals.I have done it with success but this isn't the norm.I have had 2 differen't pairs(well 2 differn't males,same female) spawn in my 135.Out of maybe 10 spawns i had to move 2 fish that the male saw as the biggest threat but other than that it's worked.With mine as long as the other fish stay on thier side of the tank and retreat when told it has worked.
Nice setup and gl with whatever You go with.I'd definitely give the Festae a try though.They are one of My favorite pairs to keep