Billy McKinney was the only Cub with an insert, being included in the sticker set. And he's not even Cub property, being traded to the Yankees in the Chapman trade.
While McKinney was the only Cub minor league player in the inserts, two Cub affiliated mascots were also in the sticker set.
Both of these characters are with the Myrtle Beach pelicans.
With these in hand, I believe I am now officially done with Heritage for 2016.