Lexi, your post raises a good question: is passer-by hyphenated?

Some dictionaries list is as a compound word and others list is as hyphenated. The strange thing is that, even when it is listed as a compound word (as in Merriam Webster's online dictionary), the plural is made by inserting an 's' into the word, making the plural of 'passerby' (the compound version) 'passersby' in direct contradiction of what you are saying.

goofy,

"you, and I" in that Shakespearean sentence are in the vocative case. They are not objects of any verb, nor are they possessives, and thus provide nothing for this discussion.