Smart on waiting for the pike, it would be do-able in a 125 for sure, I would wait for then.
JD females will become sexually mature and able to breed quite small, 3" or so. However the male may be abusive to such a smaller fish, hard to say depends on your male JD.
The love hate relationship with cichlids, the personality can be their best and worst trait. I will call around to some fish stores in my area to see if I could order in possibly 4" female JD's, being in New Hampshire, the quality of LFS is pretty slim in my area.
I have never used a divider before but would this be a good idea to section off the tank with the females on one side? Have you or anyone else tried a divider that the smaller female can get through but the males cannot?