Use Pokémon of correct type, or with correct type attacks?
Suppose I'm fighting a fire-type Pokémon. Suppose I have a water-type Pokémon but it doesn't have water-type attacks. Suppose I also have another Pokémon that isn't water-type, but it does have water-type attacks. Which Pokémon is going to be more effective fighting the fire-type Pokémon?
(Obviously this is a hypothetical question. We can't have the most ideal attacks on all our Pokémon. For situations in which I cannot fill a six-pack of Pokémon that are both the correct type and have the correct type of attacks to use against a boss, I want to know if I should fill out the six-pack with Pokémon that are the correct type, or if I should prefer ones that have the correct type of attack even if the Pokémon type is wrong for that encounter.)
Answers
Type effectiveness is a multiplier of 1.4x, and damage resistance is a multiplier of something like .714x. Because this game runs on timed battles, speed is usually the best bet to winning battles, so using a non-water type with water type moves would be better than using neutral moves on a Pokemon but resisting their fire moves.
However, if you're on your last Pokemon or two and you're trying to survive 'til the end, that's when I would use the water type.
In short:
Lead in with an effective attacker
End your team with a resistance Pokemon