can you tell me some ins and out of invading? i know how to but what helps the most? like dose ship defense count at all towards invasion offensively? thanks for all your help

Invading, ship only counts the attack stat

For defending planet, to reduce invasion success %, Att+def+invasion def are counted.

does the attack strength help the % or is that only used to reduce the population to invasion levels?

Attack of ship helps to increase % of invasion success.

Amount of reduction of pop is counted somehow like a normal battle, so yes, more attack would deal more damage