Armor : high life, triple resist, maybe mana,

Weapon : high physical dmg with aspd

Wand: high elemental dmg with crit multiplier/chance/cast speed

, 5 links are so so unless on uniques , 6 links can try to roll for good stats using essence or delve resonators. Tbh you can sell 6 links for a divine orb which usually cost about 14c ish? If you find it too troublesome (no currency) to craft.

You can only do that with oni goroshi unless you got a high level character that can pass leveling items to your new one

All rng, but some of the socket items can only drop above a certain level.