Reb Eliezer,
“Use your common saichel”
You and rational have brought in sources but have failed to answer this specific shaila. You talk about tircha b’tzibbur, but kaddish yasom said by a chiyuv is NOT tircha b’tzibbur. And rational brings halachos about a non-chiyuv saying kaddish yasom, but we are talking about a chiyuv. This is not a matter of what’s the bracha on corn flakes. This is a real shaila that deserves to be asked. And given Always_Ask_Question’s clear lack of knowledge of the halachic process, I am rather surprised that you would discourage him from asking a shaila of a rav. That’s dangerous.