I didn't expect him to get perfect grades since he's trying to blend in, but did he screw up his exams that badly ? Because Lyra's reaction to his grades seems pretty extreme.
I hope that Harry discovers a method to erase or distory the memory of his Parents about his revelation of his transmigration. It's seriously annoying in the story if the MC's parents try to interfere in his actions.
I hope that Harry Performs a basic Horcux ritual on Neville to check if Voldemort's Soul is in him or not. If Nevilla is a living Horucux then Harry should try to eliminate the part of Voldemort's Souls without Killing Neville. In this process, Harry should get the ability of Parlsemouth.