The amiibo situation gets crazier with each passing wave. The running joke among the community is that every figure will be rare in Wave 4. You know what? That could happen.
Based on an internal memo that just went out nationally to GameStop, a few provisos are in effect for some characters. Ike will apparently be fulfilled in two waves. If you ordered him beforeDecember 26, 2014 (wow!), you will likely get your pre-order this week. If you didn’t nab him until after that time, your order may be delayed into spring.
You will likely get a call stating that your figure is in, but even if you have multiple paid pre-orders, GameStop will not honor more than one per household. Major bummer for people who have multiple children — I even pre-ordered an extra myself for a colleague.
King Dedede will also be fulfilled in multiple sessions. He will be at most stores on Wednesday, February 25 if you ordered before December 30, 2015, but for the rest of you, expect him in summer. Mega Man and Sonic orders will all be fulfilled, and should be in by next Wednesday.
I have independently verified the authenticity of the memo with a source. Plan accordingly, and pre-order Wave 4 as soon as you can, since GameStop is prioritizing people who ordered this wave two months ago.