Can say Superior Spider-Man and Iron Spider both start with the Waldo Arms object if on the same starting force, as long as you have 2 Waldo Arms objects?

Yes, the objects are considered to come from outside the game so they are not checked for uniqueness when starting equipped from a trait even if you have to pay for the trait or if it is for free.

When the Waldo Arms equip, is at the beginning of the game, after establishing themes teams and checking for unique objects.

Relevant WIN Ruling

TMT 062 Thunderstrike