I’ve just checked your questions.
For “você/s” not being formal, you are right. This works only for European Portuguese and was added to the Brazilian course by mistake. Sorry for that! I’ve just fixed those entries.
As for your "in the morning" question, it’s not wrong, but can be clearer. Here’s the explanation:
"In the morning (a.m.)" refers to the way we say time in Portuguese. So, "10:00 a.m. / in the morning" would be "10 da manhã", whereas "pela manhã" refers to "in the morning" as a general way to mention the morning period of a day, like in “we did that in the morning” = “fizemos aquilo pela manhã”.
Thus, your speed review probably presented "da manhã" in that question, instead of "pela manhã".
Anyway, I’ve also changed this one, which now is presented as “da manhã” = “in the morning (time; a.m.)”. Same goes for “in the afternoon = da tarde” and “in the evening / night = da noite”).
Hope this can avoid other mistakes.
Do let me know in case you have any other questions!