I have a doubt, does the gog connect redeem only standard editions? or the deluxe or season pass editions too?
I'm planning on getting Age of Wonders with season pass on steam and link it here (Because it is cheaper on steam in my country)
It will only allow you to redeem the standard/base edition of a game. This has something to do with the Steam API side of things, if I remember correctly. The way Steam treats DLC and the like - they don't (normally) appear as a game entry in a user's library there and since that's how GOG's end checks against what an account has there, it can't grant something it cannot see. So you'll either have to re-purchase any additional content or be satisfied with owning it through Steam if you'd rather not do so.
An exception to the above would be if the only available edition is an updated one (GOTY, "deluxe", etc.) but off the top of my head I can only recall one time that any such title was up on Connect like that and it was Omerta: City of Gangsters Gold and it was taken down from Connect before its official expiry time because people couldn't get it to be properly recognized despite having the game present in their Steam libraries.