Been gone for a bit... someone catch me up. Restocks and 4a?? What about US Robin/Lucina/Silver Mario, and waves 5 plus?
Japan has gotten restocks of pretty much all the rare Wave 1/2 amiibo, with a Rosalina restock in June, so imports are looking good right now. Worldwide there have been restocks of Marth, Ike, and Meta Knight. And signs of Lucario/Dedede restocks. Only NWS has had any real stock, so while prices on many have gone down, it's still high and dry in the USA.
Marth/Ike have been at some Gamestops, but only 2 at the most with pre-orders being priority. Meta Knight is at some Best Buy warehouse with signs of a 5/29 small restock. Lucario and some Dedede were restocked at
one TRU, but no word on the rest of the country/stuck in a warehouse.
Robin/Lucina will be the unicorns of Wave 4 as most stores are only getting 2-4. Jigglypuff/Greninja seem to be decent in number and most stores having a limit on purchases, but you should still arrive early. Silver Mario IDK, seems better in number than Gold Mario.
Wave 5a/b has pretty much already sold out on European websites. Dark Pit is potentially BB only, and Palutena potentially being exclusive somewhere as well (Walmart?). IMO import this round as they'll be out sooner/you'll probably pay scalper prices anyway.
ROB/Mii Swordfighter prototypes have potentially been leaked. Villager has been slightly redesigned for his restock.