Improving my squad

Hey guys, I was just wondering what’s a good pokemon for my last slot that can compliment my other mons.

Blaziken (Choice Band) - Jolly - Speed boost Moves: Return, Brave Bird, Blaze kick, Sky uppercut

Staraptor (Choice Band) - Adamant - Reckless Moves: Close Combat, Quick Attack, Brave Bird, Take down

Greninja (Expert Belt) - Timid - Protean Moves: Extrasensory, Round, Ice Beam, Surf

Delta Muk (Leftovers) - Brave - Sap Sipper Moves: Recover, Stealth Rock, Return, Earthquake

Delta Charizard (Delta Charizardite) - Modest - Spirit Call Moves: Dragon Pulse, Shadow Ball, Lunar Cannon, Confuse Ray

My plan was to replace my Blaziken and Staraptor for a Lucario and a Talonflame. I also have some difficulties facing a water pokemon so a grass or an electric pokemon should suffice the last slot on my team, thanks!

I would give Blaziken a life orb instead of the choice band, take out the brave bird or the return for protect so you can get a boost against faster pokemon and outspeed them. Also Hi Jump Kick has much more power than Sky Uppercut. You can consider Flare Blitz instead of Blaze kick too, so that your Blaziken hits hard enough to clean after the pokemon that resist him are down. Low kick is a popular option in simulators because Blaziken is ubers and fights heavy legendary pokemon, but it’s not as good in game.

Greninja has round for some reason, why would you want it to be normal type if it has no resistances? Greninja is so frail that he will die unless he resists the hit. Also normal type hit no type for super effective, so why give it expert belt? Your moveset doesn’t have a lot of super effective coverage and neither good defensive typings for Greninja. I would change Round for what ever else, even a move like taunt so that it annoys stall pokemon.

Your final pokemon could be Tentacruel, being water ir resists water itself and also it provides fairy resistance that your team lacks. Blaziken being part fighting is neutral to them, greninja at first is weak, charizard is weak to them also. So Tentacruel could cover your team weaknesses to water and fairy by resisting both and having a good special defense in general.