for armor, you should always pick something with at least a small offensive boost. as you are asword/gun hybrid, you can pick the wolver line (end it in vog cub for FSC), padded line (sacred firefly sentinel or shade is great for FSC, but not that great beforehand), original gunner armor line (the sashes) or chaos for overall boosts and lots of status weakness.
for shield, I would go with something that has two status resists or offensive boosts. owlite would be a good choice.
for weapons, you should have two weapons that both deal differnt non-normal damage. you could for example go with a nightblade and an elemental blaster. even better would be if you get four weapons so you have two guns and two swords of different non-normal damage.
of course that costs a good bit, so going with plain calibur and blaster would be a cheaper alternative, albeit a weaker one.
and no, nightblade isnt not worth it. at 5* it gets a major damage boost, being on par with two hit swords in damage per hit.

He's a pretty powerful dude... ish. Maybe compared to his other swords maybe? He's an all-offensive.

Most advanced players in this game are heavily oriented toward offense. No, Acheron is not weak compared to his other swords. Acheron is one of the most powerful swords in the game (depending on the situation).

What type of Elemental gun would be good?

Well, Nova Driver and Storm Driver are powerful and fun. They have a steeper learning curve than most of the other weapons in this game. But that just makes them more interesting to me.

Some players like Arcana. It's not bad, but it's kind of boring. Wildfire and Polaris can be very useful, but you have to use them carefully, due to the huge knockback. Argent Peacemaker is mediocre and very boring. For more information, do a Google search for something like "elemental gun site:forums.spiralknights.com" (without the quotation marks). You will find many threads.

I'm planning to go the autogun path, my friend recommended, "The Grim Reaper".

You mean Grim Repeater. It's a good shadow gun. So are Umbra Driver and Winter Grave.

Neueragon, I'm planning to go the Wolver path for my armor. I think it looks amazing, when it's the Skolver, yet, isn't pricey either :)

Skolver is good armor, although Vog Cub's defense is more useful in Firestorm Citadel, where you will eventually spend a lot of time farming.

I don't understand some of your statements about price. Most armor in this game costs the same amount. For example, Skolver, Vog Cub, and Chaos all cost the same amount. Some armors are slightly more expensive, because you can find the recipes only at Basil. But don't let that stop you from getting them, if they're what you want.

The only armors that you should be disqualifying right now based on price are: Perfect Mask of Seerus, Shadow Lair armors such as Snarbolax, and event armors such as Black Kat Raiment.

Well, Bopp, technically, by "pricey" I mean by the amount you pay.

Skolver Coat and Chaos Cloak have exactly the same availability (Hall of Heroes), exactly the same costs (in terms of orbs and crowns), and similar material requirements. The same goes for their lower-star precursors.

Anyway, you'll figure it out. Or, if not, then feel free to ask more questions here. Happy travels. :)