I am not sure I understand this correctly, but can the "αυτούς" in this sentence be omitted? Is it there for emphasis?
Yes, it could. Actually the sentence is wrong... It should be αυτών (genitive) and not αυτούς (accussative). We will remove it or change it.
Ah, I think I understand then, but just to confirm: the sentence should just be Τους άρεσε η πόλη, right? That would be a simple declarative sentence- "They liked the city," yes? And it could be Αυτών τους άρεσε η πόλη and that would just be emphasizing that it is "THEY" who liked the city (as opposed to a different group of people). Do I understand correctly?
It should be αυτών τους άρεσε η πόλη, but it is used even not grammatically correct, as an attraction trope. What is this?See this http://grammarist.com/words/trope. Tropes in Greek are many. They are called σχήματα λόγου, some are the same as in English. Poetry is based on them as you can see. The σχήμα λόγου έλξης, attraction trope is thev0 following: A syntactical form which is strong, here is τους attracts a weaker, αυτούς, in the same case instead of genitive, αυτούς in accusative as τους, even though it is not grammatically correct. So as it is used this form even wrong. Many examples of tropes like this here: http://users.sch.gr/ipap/NEGlossa/sximata-logou-NE.htm#13