A few quick questions, please help.

Arcane (full int with str to wear latest arcane armor, or 4.5 mag, 0.5 str) is the quickest for leveling. Yes you can redo your stats later on (costs 5 gold in the cash shop). Most venos going for a heavy build start off arcane to level, then restat later.

Light build is 3 mag, 1 str, 1 dex every level. You have two extra points you can put into vit or mag. It's a "happy medium" which is a lot easier (less complicated) to use as a leveling build. The stat and armor requirements are straightforward.

Heavy (or the heavy/arcane mix) is the hardest build to pull off because you don't get enough stat points to wear the best heavy armor (~2 str and 0.6 dex per level) and wield the best magic weapon (3 mag per level) at the same time. You have to wear lower level heavy armor, wield a lower level weapon, or acquire jewelry which gives you +stat bonuses to let you meet the requirement. So most venos opting for this build just do a regular arcane build until about level 70, then restat to heavy.

Numerically, using the magic defense bonus of arcane armor of 100 as a baseline:

Arcane: 11 p.def, 100 m.def
Light: 44 p.def, 67 m.def
Heavy: 100 p.def, 43 m.def

Heavy/Arcane mix (theoretical): covers entire range, but average is 55 p.def, 71 m.def
Realistically you can't achieve the H/A theoretical prior to about level 70 unless you've got a ton of +stat bonuses or go with a lower level weapon. Without the bonuses and using lower level heavy armor, it ends up being about the same as light armor, just a lot more complicated.

If so, I would like to switch to a Fox build for PvP. Which would be best? I've heard about Light Armor Foxes .. Are they any good, and do you guys think there is a better build?

Depends when you want to start PvP. If you want to get into it immediately at level 30, light armor is probably the easier option. At 70, restat to reallocate some dex to str and move to a heavy build. If you're willing to wait until you're in your 60s or 70s to join TWs, then go arcane to power level yourself to that point, and restat to heavy. I should warn you, doing this you will spend a lot of money buying jewelry with +stat bonuses and armor with -stat requirements.

Prior to about level 30, I wouldn't even bother worrying about armor. I made it all the way to 30 using just the quest armors and random drops I got. After 30, things start slowing down. Check the quests on www.1perfectworld.com to see what armor pieces you can expect as rewards. Check www.pwdatabase.com to find the Rank gear (search for "tamer" to see the Rank I veno gear). The other stuff you're best off searching and bidding on the auction house. Do not buy from NPCs - their prices are more expensive than you can get off the auction house.

Welcome to lost city. Just so you know you joined a pvp server so at lvl 30 you are fair game to everyone lvl 30+ to pk or for you to try to pk.