Reason to get pottery first: we can get a granary in the copper city and grow it to size 4 quicker. A definate benefit to the economy, it gets a strong production city up to speed sooner, and it wil decrease the time taken to reach size 5 and 6 when we hook up our happiness resources. I think that getting 1 warrior out of the copper city then building a granary with a forest chop is an acceptable compromise considering our current technological and explorational (is that even a word?) position, as it allows us to explore to the west and north of the copper city for other viable city spots that may contain horses, and allows the city to grow to size 4 and pump out a settler (the units to defend the city could be built while growing) in a decent amount of time, so we are not relying solely on the capital for workers and settlers.
Reason to get AH first: we know where horses are earlier. No benefit to the economy, though we can plan to get a horse city third instead of a city for the elephants earlier and hence tailor our plans accordingly. (Though personally, as we have copper, horses are only useful to scout with and kill an axe stack with right now, so I would vote for the ele city as the third city, and consider a quick fourth city for the horses against other plans)