I have read that the FFOF can sometimes be a little hot for starting seeds, Maybe you have got a bag of hot FFOF that might be what is killing them
Ok the 3 in reg potting soil and HF are all about 2" tall; what is a typical heighth/time you would transplant to their final buckets? We've kinda been leaning on books for info but it seams to be in our best interest to talk to you all on here who do this stuff every day..
Take care and as always we appreciate the help!!!!