secondary side current control
All good stuff, alternatively you could transformer couple your mosfet drive signals and then only the swiching transistors and the switching transformer primary will be mains live. You do require some clipping zener diodes to shape up the pulses a bit and an RD network is also required to rapidly discharge the gate capacitance on switch off. In this case the mosfet driver device is not required. Design your driver transformer with a 1:1 ratio with enough turns to generate the required output voltage without overloading the controller chip, I have not had any trouble driving normal sized mosfets directly using this method but it is necessary to include all the required protection components on the gate drive. If you are worried about the driver chip, include complementary NPN/PNP emitter followers (configured like transistor radio af amp outputs used to be) to drive the transformer inputs, they do not need to be big, 2n2222a/2n3907a will do it, the driver signals are already available in complimentary form.
WARNING, as you have got it, it is a potentially lethal power supply, make sure you remove the mains coupling to the DC outputs, no matter what else you do.
The heating and the noise is probably due to the control loop being destabilized.
Good luck,
Bob.