Disclaimer: Not a computer expert but just giving my opinion on your purchase.
Why did you get a motherboard with a outdated cpu socket? I would recommend getting atleast am3+ socket motherboard. Which will then make your cpu incompatible so I recommend getting atleast a AMD 6300FX. As for your gpu, while the 970 is a great card, I believe it cost more then a new 1060 which is an even better card so opt for a 1060 if you can. That's pretty much what Id recommend.
Please use the image tag when linking to photo next time.
As for the fog problem, that looks like radiant fog. To fix this first BACKUP YOUR MAP then Open your map in Radiant, Hit the "I" key to select everything, then drop your whole map upwards. The fog is from your map being too close to the bottom of radiant. So dragging your map upwards a bit should get rid of the fog.
I haven't a clue then. All I can say is try re-watching what ever tutorial you followed and maybe you may find a step you missed? Also for importing from older cods, are you making sure to remove the extra _t7 namespace via notepad?
You need to make a world model for your weapon. Use wraith and extract a weapon's world model from Black Ops 3 and import it into maya. Then import the weapon you want to make a world model for into maya as well and position it similar to how the bo3 weapon world model looks.(Line up the weapon trigger). Then delete the bo3 world model, manually bind the new world model. Then import into bo3 and it should be in hand now. Keep in mind that if you want to do pistol, then extract a pistol world model and so on.
Also make sure your player anim type match the animations for the weapon. Exapmle. Pistil anim type for pistols.
P.S. If you ported a weapon from a older cod. It's either A, BO3 uses different orientations for wirld model. Then do what I stated above about exporting world models and replicating what's shown. Or B, you didn't change the player anim type to the correct corresponding weapon type. Then you'll do what I stated for the weapon file. The weapon file step is done for both regardless. So I would check your weapon file first to make sure it's correct.
There is a setting for isHybridWeapon in the weapon file. As for how'd you actually port it,it's most likely just using the alt weapon file in the weapon file settings I believe. Not entirely sure though.