The
Hunstman is fully charged after about three seconds. The charge bar is in the bottom right below your ammo count. The more charged it is, the more damage. But, if you hold it too long, when the arrow is shot, it will go in a random direction. So you can't hold back on the bow forever.
The fact the Huntsman is used in the crafting of the Crusader's Crossbow or Sydney Sleeper doesn't matter. You can get both without crafting them. The
Sydney Sleeper is a Sniper weapon and better if you want to peg targets with Jarate, meaning they will take mini-crits when damaged again. Keep in mind you can't get headshot kills with the Sleeper. The
Crusader's Crossbow is for the Medic and can be used to heal friendly units or damage enemy units based on distance fired.
The best Spy melee weapon is based on personal preference. Here's all the melee weapons the spy can use.
LinkGenerally, the stock knife is good since it has no negative effects. Most the other knives have negative effects. It all depends on play style.
Your Eternal Reward has the effect of killing a target without making noise. It also disguise's you as the last person you back stabbed. However, you lose the ability to disguise, so getting the first kill is usually the hardest part.
The
Dead Ringer is a spy cloak device. When active, you can't shot or stab people. If damaged, the spy will perform a feign (aka fake) death. Though the spy appears to have died, he is actually cloaked. When uncloaking, the dead ringer makes a really loud noise, so it's best to be a distance away from the enemy when you uncloak. So basically, the Dead Ringer works by making the enemy think you are dead, allowing you to get behind enemy lines quickly.
The
Pip-Boy can be dropped, crafted, or purchased. It's just a cosmetic item for the engineer. Genuine ones were promotional and can't be gotten anymore. It changes the color of your construction options to green.
Vintage/Genuine/Other qualities describe what the items is. They are not from tags. Genuine items are TF2 promo items from other games, usually from pre-purchase. Vintage items were available before the recent economy update. They can no longer be found. There is no difference between different quality items. It is purely cosmetic.
When in doubt, check out the official TF2 wikia (not tf2wiki).
http://wiki.teamfortress.com/wiki/Main_Page You will find most your answers here.