The non-team thing is common but they do it to bring “objectivity” to the process and since it’s leetcode or system design questions, it usually doesn’t matter unless you’re applying for a highly specialized role.
I can speak for google and Amazon - you might not even apply for a specific team till you’re in, and do that afterwards. Facebook also did team match post boot camp.
Hell, they admitted as much a few years ago... and claimed they were going to try to be better.
Needless to say I was pissed.
He went on a Google interview, and they said he could solve a problem in the language of his choice. They gave him the assignment and left the room. Since we were at Apple at the time, he was coding daily in Objective-C. So he solved the problem in that.
Despite having said "use any language," the guy came back and said, "Oh, not THAT one."
And that's not even covering the douchebaggery that reportedly occurs once you work there. Another trusted friend, who worked there for years, reported being forced to rank coworkers with a graphical tool that shows pictures of them... and requires you to move them up or down on the screen to put some above others. It makes it impossible for you to put people on an equal level.
This is not from someone who makes stuff up, not to mention that this would be an oddly detailed thing to make up.
"Leadership principles" sound like Amazon. As far as I know they purposely get all their SDEs involved in hiring, and the bulk of their interviews is based on hard-skills, even when the interviewer's goal is to assess "leadership principles".
Also, one of their explicit interview goals is to have the candidate leave the interview round with a good impression of the company.
Nothing in your story adds up. Either you're embellishing it too hard or you're misusing the FANG keyword.
None of the FANGs I know ever had non-software engineers interview candidates for SDE positions, specially when software development managers are primarily software engineers themselves and interviews have a considerable software development aspect.
I'm sorry to say but your story doesn't add up.
Overall, I somewhat expected such an experience and am glad I ended up where I did. The place I am going is filled with great people, and honestly, more intelligent and curious people.