6th Poke needs help please...

[Pig on the Wing]

Right, i'll cut straight to the chase.
I need a 6th Pokemon for my Ruby team, but before anyone says anything there's a few things you need to bear in mind beforehand please:

(1) It's on Ruby and I have no access to Sapphire/cheat cartridge.
(2) No legendaries/semi-legendaries/Ubers please.
(3) I'd prefer it to be a happy fun Pokemon.
(4) Only R/S Pokemon.
(6) Please include moveset/items/nature and ability.
(5) It's fighting alongside:
Swampert <> Swellow <> Zangoose <> Absol <> Tropius

Thanks in advance people.

[Poryhedron]

If you want us to include moveset, items, nature and ability, you should do so as well...for the five currently on your team. These things need to mesh, after all. If all five of your pokémon are sweepers, we need to know that so we don't suggest a sixth sweeper. If your team relies on weather effects or something, we need to know that so we don't suggest a pokémon that would interfere with that central stratagem.

[Ultimate Pikachu]

So far your team is unbalanced. I don't like Tropius, it's defences are average and attack stats are low. I assume you have no acsess to Fire Red and Leaf Green and Swords Dance is what can make Tropius good. It's more suited to be a tank but doesn't get good tanking moves. I would suggest Dusclops.

Dusclops
@Leftovers
Bold/Calm

Will-O-Wisp
Calm Mind
Ice Beam
Rest

Do you know about EVs? If so, I will make EV suggestions.

[rinku]

Tropius is a fine pokémon. But it really does best in the sunshine. My suggestion would be a 6th with a Sunny Day focus. In terms of "happy, fun" I'd suggest Castform:

Weather Ball
Sunny Day
Solarbeam/Thunder
Rain Dance (to boost Swampert)

This will also be useful vs Steel, which your team may have an issue with depending on their moves.

Otherwise, perhaps a regulation Fire type like Ninetales?