1) Triple UV: Max piercing, elemental, and fire. It's impossible to be "all around" with just one UV. Normal will cover the most amount of damage types you encounter, but you will still be vulnerable to everything else that's not shadow. Choose whichever you get hit by most (ie jelly spikes, gun puppies, howlitzers, lag spikes into traps) and decide with that.

2) For selling? Mats like Philoso Feather, Silverweave, Trojan Horseshoes, Mug of Misery. Best off just saving them for whatever mats you need. The trinkets require you to unbind them to sell which costs 4000 ce, and no one is going to pay for that. If you plan on using the trinket yourself, you're better off going for the weapon trinkets instead.

3) Resists reduce the duration of curse. You will not be seeing less self-inflicted curses. There is reason to believe that a really large amount of curse resists will reduce the rate and damage of being cursed, but that won't be happening with just those two items you have: http://wiki.spiralknights.com/Curse

The GF charge attack is always fun and powerful, but you will always be in risk of cursing yourself. If you insist on using the charge, just carry 4 weapons in case it happens. And you're better off with an attack speed UV rather than a CTR.

EC: Depends on what you're missing. Aim for max attack speed and max damage with your gear. For example: Full snarby set + barb shield + 2 sword attack speed trinkets + medium asi UVs on all your swords.