Well I got extremely impatient on getting all the Sun Stones so I used my Action Replay to get them and raise all the islands. But I think that was bad because now Mark won't come Dx I went to every island and unlocked every other character and talked to every character, so why won't Mark come? =[ Is it because I used Action Replay, and that confused the game or something?
I just looked up Mark on fogu and it says you need to have built a bridge to Link Island in order to discover Tree, Rice, and Greenhouse Islands. Have you done that?
Did you unlock all the islands, including Sunny Island?
That's the only other thing I can think of... Mark comes when every island but Sunny Island has been raised. So maybe you raised them all too fast?
The site also says you need to have unlocked all the other characters, like everyone from Mystic and Mushroom (not the traveling characters, though). The Harvest Sprite only lets you raise one island per day, and since it seems like you can only have one "event" per day, maybe it's possible somehow that Mark got skipped in favor of another daily event, and as a result, he wasn't unlocked between raising the second-to-last island and Sunny Island. I have no idea if that's the case, just putting the thought out there.