Yep as long as the caps in the control circuit power supply mains filters are Class Y, it looks like at worst you need to isolate the heatsink for the triacs.
Looks like a fairly conventional DMX512 input stage lighting rack to me, I am somewat surprised that rolling your own is cost effective.
Now given this thing is going to be fed from a supply somewhat larger then domestic (32 or 63A is conventional over here),you may also wish to carefully consider the breaking capaicity of your fuses and how much you may wish to oversize your power semis by (Compare the surge current rating of the triacs with the fusing curve for your fuses).
Regards, Dan.