You are certainly correct that that sort of thing would have gone (and indeed did go) right over my head.
And I have no doubt that there are innumerable bits of American culture that would mystify, or be missed by, those from other cultures.
It still leaves me wondering what the actual story purpose would have been. We already know that this is an exclusive and apparently quite pricey school, with the assumption that the students come from relatively privileged backgrounds. Stephen is a Viscount, although he seems to resist at least some of the implications of that title. He shows pluck along with his occasionally short fuse. It's not clear what light his drinking habits might shed on his character in addition.
I have become far more accustomed to the British way of expressing things as a result, among other things, of reading stories here. Apart from terminology differences, such as "living room" here and "lounge" there, there are verb form differences. In the US we would not say something like, "I found Marge and her sister sat in front of the television." We would use the present participle, "sitting," rather than "sat." Similarly, we use the present subjunctive as follows: "Bill suggested that we go after lunch." rather than "Bill suggested that we went after lunch" where "went" is not subjunctive (I'm not really sure what it is). And so on. I've gotten used to it. I assume British teachers would not have marked either of my examples wrong. In the US they would have.
I will almost certainly be appreciative of any efforts you undertake to make your new story more understandable to Yanks. Although I do not recall any particular challenges with the previous ones.
R