I think the 15 is mostly a grammar thing. After reading I can see more then a few common grammar mistakes. Your assumptions are mostly correct, So I see no real reason to dock points for those. Some simple stuff I could point out real quick, most of which is underlined in red;
fre quent is actually one word, frequent, no biggy, I've done that in french a few times myself.
Shakespeare's, forgot the apostrophe and s. x)
whenever you use a quote, "there is always a preceding comma"
and so; "The quote, "o' brave new world" appears multiple times. Each version of this quote however, implies a different feeling."
oh god stop me please, I can go on for days x.x gegege