Is wearing a qamis instead of trousers considered a "libas shuhra" (garment of fame/ostentation) within the university, and is it better to wear trousers—the common dress of the people of the land—in this case?

There is no harm in wearing modest trousers (pants), and it is not considered an imitation of the immoral or the disbelievers. The basic principle regarding clothing is permissibility, except for what is explicitly prohibited by evidence. As for wearing a thobe (qamis) to emulate the Prophet (peace and blessings be upon him), this is not considered blameworthy لباس الشهرة (clothing worn for ostentation), and there is no objection to it, even though لباس الشهرة refers to violating the common dress of a country without a valid excuse.