>>21071395As far as the anime is concerned, Scizor is Wikstorm's main Pokemon since it's his primary Mega Evolution.
>>21071435There's a chance that Inkay will evolve. Watch episode 43 again. @16 minutes in, Pikachu takes out Inkay with a single Thunderbolt before it was able to execute Psybeam, and James was clearly pissed about the whole scene. Even when Jessie and Meowth were making their escape in the following scene, James just stood there until Inkay was able to escape.
That scene shows that James does seem intent in wanting to beat Ash for once unlike Jessie and Meowth, who only care about carrying on Giovanni's orders. Hell, he didn't even have to continue attacking Ash and Korrina since he already destroyed the staircase.
Also, Malamar is needed for Team Rocket since the chances of Ash ending up with an overpowered team are very likely.