Hearing this made me create a list of amiibo I think may be discontinued before the rest of that wave:
-Marth
-Villager
-Wii Fit Trainer
-Captain Falcon
-Little Mac
-Shulk
-Meta Knight
-Lucario
-Shiek
-Zero Suit Samus
-Ness
-Mr. Game and Watch
-R.O.B.
-Duck Hunt
-Dr. Mario
-Dark Pit
-Lucina
-Mii's (off topic but do you think Mii's will get amiibo's?)
Reasoning:
Marth, Wii Fit Trainer, Villager already gone
Captain Falcon and Little Mac have not had a game in a while (5 years let's assume)
Shulk, Meta Knight, and Lucario are retailer exclusive (Gamestop, Best Buy, and Toys r Us (U.S. only, no idea what equivalent for other regions would be)
Shiek, Ness, and Zero Suit Samus are honestly random guesses
R.O.B., Mr. Game and Watch, and Duck Hunt due to being retro (I actually should buy a duck hunt amiibo)
Dark Pit, Lucina, and Dr. Mario due to clone status
Everyone else I think may be available awhile (assuming nothing else comes up)