I have no problems with us bedding brakes in, in different ways
With any semi-metallic I will use the same 100-20 as you describe, but I do give them 300 km of normal driving first.
Heat cycled discs? Well, with my educational background I assume that the discs are cast, cooled off in stages. Then machined (maybe at slightly elevated temperature), and then "normalized" in a heating and cooling staged cycle. The tension around the holes needs to be relieved. Remember, ALL discs have holes....one for the hub and 3,4,5 or 6 for the bolts
I do not expect normal street discs to have been heat cycled multiple times and not to anywhere near the temperature they reach on the road during a hard run.
The extreme temperature at the braking surface is not really possible to simulate in an oven anyway. This is where bedding becomes really important. I am going to simply here, so please don't nit-pick:
Heat attracts the carbon in steel. As the braking surface gets hotter than the rest of the disc, carbon will diffuse toward the surface and harden it. This is good for disc life. However, sudden thermal shocking can create uneven hardening and cause irreparable shudder. Sometimes, as you say Ovekam, you can cure judder with hard braking. Either you are evening out the hardness because there is enough carbon in the discs to allow that, and/or you are cleaning off an uneven transfer layer.
I am having a hard time finding any official recommendation from ATE on how to bed their ceramic pads. Considering the design philosophy these ceramic pads probably create a transfer layer on the disc without needing extreme heat or pressure. Designed for "comfort" and EU regulations, they likely don't need any special bedding for most normal use.