Google "Destroyor steam in-depth faq"
For the skill/attribute check, Google each individual skills/attribute wiki page.
As for weapon combo, you just use your logic I guess?
Light weapon requires high Dex, so it's best to go with 18 dex, Versatility (+10 spec if possible), and max melee, pair it with serrated knife / energy edge combat knife.
Sniper, AR, and SMG has feat that gives free shot (shooting spree and Commando), so it's better to have 2 weapon, one with very cheap AP cost per attack/burst, and very expensive AP and very powerful ones.
Energy Pistol and Chemical Pistol works best with their own type due to flexibility of weapon elements and feats.
Crossbow generally works best with themself, but may requires quick pocket and utility belt because of so many different special bolts, but it also works as Versatility weapon.
Most heavy melee (sledgehammer, sword, spear) are almost interchangeable, you can use sledge temporarily on Sword build to cheese robot combat for example. But you still need to put focused feats according to your weapon of choice.
Nowadays, I'm very attached to 8 INT build, the extra skill points off the crafting are very welcoming. 100 effective stealth is mostly enough to do anything stealth related, as long as you're not lazy hunting at least 2 Q150 black cloth for Tabi and Cave Hopper armor. You could find 20 stealth balaclava very easily. Q160 only gives 25 stealth for comparison. Cloaking Device also helps in rare case of passing enemy on melee range.
