I think Arteta and Enrique would probably complement each other reasonably well if the former supported the latter. If Enrique were to be appointed, language and local understanding would be factors for him.
However I'm not sure Arteta would leave City to be an assistant at Arsenal.
Also, I hope we all realise we're very likely to be looking at two new managers in the next two or three seasons at the club. Arguably we should be going with an experienced "handler" now since the new arrival will be inheriting an ageing squad with a reasonably well established front half, but if that plan doesn't work out, we should be switching to a "builder" for the next phase of player recruitment.