Excellent college graduates: this word order is translated incorrectly, should it be Dipl? I am an excellent university graduate.
In fact, the word "I" in dipl itself contains the meaning of graduates, so the word "élève" can be omitted.
Mianyang Excellent Student Cadres: The word "student cadres" is difficult to translate, after all, there is no concept of this position abroad. The closest word to this meaning in French is les leaders étudiants (literally "student leaders"). Therefore, the whole translation of this word should be Mianyang Excellent Student Leader Certificate. There is no need to add another de in front of the city.