The number of creature tokens you put onto the battlefield with the last ability is determined when the ability resolves. If Chancellor of the Forge is still on the battlefield at that time, it will be counted.

A player’s “opening hand” is the hand of cards the player has after all players have taken mulligans. If players have any cards in hand that allow actions to be taken with them from a player’s opening hand, the starting player takes all such actions first in any order, followed by each other player in turn order. Then the first turn begins.