Morning magic hours start an hour before official park opening, which in regular season is usually 9 am, so morning EMH runs from 8 am to 9 am.
Evening magic hours run for 3 hours after park closing. So for example, if MK closes at 9 pm and has pm EMH, it would be from 9 pm to midnight. The times vary greatly at DHS and MK with evening EMH depending on the season and the official closing time. In the busy months MK has EMH until 3 am on the nights they run it in this park and yes, it usually starts after Wishes as that normally signals the end of the evening.
Hope this helps but feel free to ask if I haven't answered all your questions