I somehow didn't notice this awesome post and I love ghosts so I thought I'd give my $0.02:
So I have been raising ghosts for some months now. I also got them when they were L2/L3s. It took maybe 4 months for them to mature. Sadly one of the 5 died due to natural causes and the other 4 made it to adulthood. SO, one of my males just passed also to natural causes (Hunter; very unexpected, but maybe 6 months and after mating is just the end of their life cycle? I got an ooth out of it though). The other male recently died to what I'm pretty sure was sexual cannibalism (I just found Phantom's wings

). In my experience sexual cannibalism is the only time they'll cannibalize other than underfeeding. I give them 3 BBFs each, every other day, but now I'm upping it to 2 (or 3) every day.
My mistake I think was keeping all my ghosts in too small a container. An 8x8x12 is sufficient going by the double the width/length, triple the height rule but I switched to an upright 10 gallon for them. I just got two new subadult ghosts from my breeder like the next day lol, so I have 4 hosts again.
Anyway Keep them well fed and they are very communal. If you want to breed them let them all live together as young as possible and keep it that way. Its a myth that one will go for another when its just an instar or 2 under or when molting. Very communal species...!