Here are the various idea benefits of native ideas...
Native Administrative Ideas -
Idea 1: Build Cost
Idea 2: Global Tax Modifier
Idea 3: Stability Cost Modifier
Idea 4: Global Revolt Risk Reduction
Idea 5: -100% Admin tech cost reduction
Native Diplomacy Ideas -
Idea 1: Unknown, New Modifier (Probably related to resettlement mechanics)
Idea 2: Diplomatic Reputation
Idea 3: Relations Decay of Me
Idea 4: Colonist (Probably +1)
Idea 5: Diplo tech cost reduction (Probably -100%)
Native Military Ideas -
Idea 1: Land Morale
Idea 2: Leader Shock (Probably +1)
Idea 3: Land Force Limit
Idea 4: Land Attrition Reduction
Idea 5: Mil tech cost reduction (Probably -100%)
The lightning bulb next to each idea group also indicates that there are benefits to completing the idea groups, but those benefits are, if they exist, completely unknown.
1) I'm surprized to see this new tab with a Native warrior in the contry tabs.
Shouldn't this replace the technology tab, or do Natives keep a technology tab, for example in case they westernize? (I undestand this may be work in progress, but this 11th tab is quite suprising, because implying it was re-made )
You can still research normal techs and take normal ideas while taking native ideas on top of those.