Got my car back today
here is what they told me: Somehow the kid (their description) cross threaded the lug nuts on the studs. They got stuck before being torqued all the way down thus the wheel was loose causing the knocking sound I was hearing. They had to snap the studs to get the wheel off thus the need to replace them. They said the person no longer works there which I feel kind of bad someone got fired over it but if you can't handle rotating tires without breaking stuff, you probably should find something else to do. Mistakes happen I guess. Here are the part numbers that were replaced:
All part numbers are Toyota, not Subaru (from what a google search says.) Odds are they just didn't carry them in stock because I doubt they replace studs on an FR-S that often (if ever.) The second picture there is of a part bag I found in my car. According to google it's a floor mat clip. No clue why that was in my car, I'll have to check if they accidentally snapped one of the floor mat clips off and had to replace it. Anyway I am pumped to have my car back, driving that tC around for 4 days was not the best haha