I think you need the Gungans (just not stupid Gungans).

I see them like native Americans during the American Civil War.

Their initial attitude would be resentment to both sides, it was always their planet and the Naboo and the Neimoidians are both invaders (all be it that the Naboo have been around long enough to be established as a seperate community).

They just want them to both bugger off.

But in the end they figure that the Naboo aren't a threat to their current way of life but the Trade Federation are and join sides with them.