Ok lets see:
Laser rifle = 45hex range shit against metal armors 80% damage reduction. 90+ dmg critical in eyes/head. Cheap ammo(spends 1 per shot) easy to craft/loot.
Plasma rifle = 25 range, awesome damage/no armor protection aim in head/eyes fatal. Cheap ammo, hard to craft/loot.
Anyway you need perception 6-7 to see enemy, and just to have % to hit. +-1 pe gives you +-15% chanse to hit.
Laser pistol is useless. Plasma pistol is not bad, it does 15-35 base dmg can hit up to 80-100 dmg critical. but 20hex range makes it a lot worse then plasma rifle. You want to use short range weapons only in towns with lots of buildings and no windows.
Here we go: Traits > Night Person / Small frame
Stats: ST 3/PE 7/EN 4/CH 1/IN 6/AG 10/LK 10/
Tag: Energy weapons/ First Aid/ Doctor;Outdoorsman;Smallguns (it can be universal sniper with energy and small guns, but prolly will lack some skill points, so adding to intelligence can help, I never tried)
Endurance can also be 6 if you want toughness on third lvl. Then you have to lower agility to 8. Or you can always lower luck to 6 (no less) if you want more endurance. Anyway leave alone perception and strength, they are fixed with the following:
You have to take
Weapon Handling & Sharpshoter which are the strongest perks for a fighter imo, check requirement for sharpshoter so you don't screw up. Just don't have starting lower then this: PE 7/IN 6/AG 6/LK 6 those are required for fighter perks(more critical and so on)
Perks: 3 Awarenes/Toughness ; 6 Sharpshoter ; 9 More critical ; 12 Lifegiver(Wep.Handling) ; 15 Lifegiver(Living anatomy if 60%doc) ; 18 Wep.Handling(More critical) ; 21 Better critical.
You can take more critical, or lifegivers your choice... Take Better critical if you want to have instant kills ( you know you want this
and you only need better critical to score an instant kill, you don't need more criticals, but they increase chance of scoring a critical and aimed critical can be an instant kill - read on wiki for more info)
Thats the best build I can give you. Also you want to have as much AG as possible 6;8;10( 7;9 are same like 6;8 ) note that character with 10 AG will regenerate his 10ap with same speed as character with 2 AG regenerates his 6ap, so he'll regenerate 4ap faster.
Based on personal experience.