I can only speak to chef mickey's but time will completely depend on where in the character cycle you end up. If you get seated right after one has passed your table, you might end up waiting a while for that round to end, a short break for the character and the next round to start up. Then again we've been in and out in less than a half hour because we lucked out and got to see all the characters right after we got our food. 45min - 1 hour probably isn't a bad estimate from when you get seated for a buffet if you plan on seeing all the characters.