The consensus is that pure thieves are useless in BG2, since you will easily reach the necessary skill cap for every situation and you have alternatives like spells, potions and such. For the basics like finding traps, disarming and opening locks thieves have too many skillpoints, thus a kit or multiclass that cuts that number doesn't hinder the role.

BTW, I disagree on backstab being useless. It's a good skill, you can one-shot some early game mages and even attempt playing BG like Commandos/Desperados, it's fun. Of course invisibility potions and spells allow for the backstab anyway, so you can exploit that.

My current run is an evil half-orc fighter/thief that focuses on stealth and traps. Currently I'm at the beginning of ToB where I left for Watchers Keep before dealing with Yaga Shura. I spent 180 points on both, on Move Silently as well as on Hide in Shadows. As a consequence, I do rely on NPC thieves for finding/disarming traps and open locks. If you put your focus on the basic skills you might have to use potions and items to boost your stealth skills.

Weapons:
Staffs ++
2-handed weapon style +
Long Swords ++
Dual Wield ++ (preparation for BG2)
Scimitars ++ (BG2/ToB)
Perhaps not the strongest dual wielding setup, but versatile and party friendly.

BG1:
I took Imoen with me and dualed her to a mage in a small party before I took up my 5th party member. Before my group finally faced Sarevok, all of them level capped. The character was quite strong - e.g. the character was able to take out the bandit camp alone while the group consisted of 4 characters at that time and was not too overpowered level wise. Backstabbing was really fun.

SoD:
I took Safana with me as my basic thief and started using traps a lot. Occasionally, I backstabbed some enemies but just for the fun of doing so. Due to the available items, I found SoD very easy to play.

BG2:
I have Jan with me to cover the basic thief skills and to have some spells at hand. Backstabbing of my character made many of the encounters easier. The character started dual wielding after obtaining Belm and switched to Scarlet Ninja'To with the gain of UAI. It is a solid fighter with the bonus of being able to backstab in due time. By the end of SoA and in ToB one begins to feel that Korgan has become a superior fighter who kills the same type of enemy faster than my character does.

As a half-elf you will lose a bit of STR and CON but a fighter/thief will still be a strong character with no real downsides. I often thought about playing a thief or a kitted thief but in the end I never started such a run because I didn't want to rely too much on certain abilities.