Myates has wonderful tips and advice. Follow her advice and I am sure you will be very successful I am sure. It is a great idea to have a variety of food on hand and not just depend on the bbs cause sometimes you simply have a failed batch for no apparent reason. I always offer a variety of food with each feeding as some fry may be pickier eaters and I have noticed once I started doing this, as adults they will readily accept and at least try new food source, even if they decide later that it is not something they may be interested in. They will at least try it. The mixture of frozen that you have would be a good idea as long as the "bits" are small enough. after a month or so it may be okay, Im just not sure how small those parts are. The fry will be extremely small. So whatever they eat has to be even smaller!
As far as the bbs, I start the first batch the first day I see little wigglers. The first day I put a small amount in the tank under the nest for any fast growers who may be quicker developers. Then I make a new batch every day. You can also set you up a simple airated tank and throw in a pinch of yeast and a pinch of spirula. And I do mean a pinch. Throw in the unused bbs and grow them out for your adult fish. Doesn't take long at all if you keep it in a warm place. I just keep it above my spawn tank and heat rises, so it stays considerably warm to not have a heater. San Fransico Bay is full of brine and the ocean therre is quick cold. So even 75 degrees for an adult brine is warm. The hatchery though you want about 80*. Mine usually hatch between 18-24 hours. But you don't want to just have bbs and nothing else cause its stressful to have a failed batch and a tank full of hungry fry!
Congratulations on your spawn!! I can't wait to see how this turns out!