Make the 12V 7A output the main output, the 5V can have an efficient buck reg off the 12V

Make the 45V o/p the next main output and generate the +/- 15V @ 1A each off the 45V

also the -5V output ( off the 45V one )

Boost the 45V up to 300V for that output ...

Now you only have 2 main outputs, each with load, that will make then easier to balance in a flyback ...

you're welcome ...

A possible fit for this application might be a flyback design utilizing the TOP271EG, with 3uF/w bulk filter capacitor (~470uF). There are a large number of outputs, and cross-regulation will definitely be an issue. It is essential to know the minimum and maximum currents for each output, as well as the required regulation for each output. As the previous responder noted, some consolidation of outputs may be possible, though his proposed solution would be very parts-intensive. Once I know more about the load ranges and regulation requirements, I can offer more guidance. For example - making the 12V/7A output one of the master output is sensible, but is there a situation where that output will go to zero load, with max load on the other outputs, or conversely, max load on the main and zero load on some of the other outputs?