1. Steel Helms should be Priority Number One for all Military dwarves (possibly for all dwarves).
2. Melting Leggings actually gives you more metal back then what you used to make them. You can make and melt Steel Leggings over and over to simultaneously train Armorsmithing and increase your steel supply. The same can be done for Weaponsmithing and Giant Serrated Disks. Although, this may be considered an exploit.
3. Bronze is better than nothing, but it's only average for metal armor. I believe the progression is Nothing/Clothes<Leather<Copper<Bronze/Bismuth Bronze=Iron<Steel<Candy.
4. Anything, even Clothing should protect from crap quality wooden training spears in a danger room. Cloaks are useful because they cover from head to toe. High quality spears may penetrate armor of lesser materials.
5. Silver cannot hold a sharp edge very well, thus it is useless for edged weapons such as swords, axes and bolts (Bolts are edged now) (saw you're using .34, bolts aren't edged in .34, so silver is fine for them). However, Silver is fairly dense, this and a few other of it's material properties make it comparable to steel for blunt weapons such as maces and warhammers. If you're short on steel, silver hammers will work just fine.
6. Spears are generally better for attacking large creatures, such as elephants, dragons and the like, because they pierce deeper into their bodies, making hitting vital organs more likely. Blunt weapons are useful against humanoid enemies wearing armor (read: Goblins) because the force behind their blows can shatter bone and bruise organs through armor (in practice, this means a Hammer Lord may quickly cripple an enemy, but may take some time finally beating through his helm and skull for the kill). Axes are great for lopping off limbs, but they might not be able to pierce very far to hit vitals, so you'll be waiting for a beheading, bisection or bleed out for a kill. Swords are basically the middle ground, they have all types of attacks, but they aren't the best at anything (the randomness of attacks also leads to dwarfs occasionally trying to repeatedly stab something they should be slashing, or vice versa). Some people boil it down to Hammer for humanoid armor wearers and spears for monsters, but that's not a hard and fast rule.
7. Using a pick as a weapon works off the mining skill, but you need to specify in the dwarf's uniform that he has to use a pick, not just "Individual Choice" or whatever. Picks are similar to whips in effectiveness (that is to say, very good), but you can more easily control the material and quality of your picks.
Take this all with a grain of salt, as I'm mostly going off of memory of what I've read here and on the wiki.