.... The question has been answers so many times... I know the answers, but I'm getting confused on so much of this... Anyways um...
During rain, Thunder gets 100% accuracy, but that doesn't make it a never miss move (like Shock Wave), so if the opponents evasioncy is up, it would still take a chance of missing.
All other electric type moves are unaffected, water type moves gain 50% damage and fire type moves are weakened 50%.
As for the 30% chance of hitting threw Protect/Detec in D/P, I cannot confirm...