If you activate Gideon Jura’s third ability and then a creature enters the battlefield as a copy of him, that copy will be just a planeswalker, not a creature. (The effect of Gideon’s third ability isn’t copied, just as the effect of a Giant Growth, for example, wouldn’t be copied.) Since both permanents will be planeswalkers with the planeswalker type Gideon, each one will be put into his owner’s graveyard as a state-based action due to the “planeswalker uniqueness rule.”