Can he be recruited if you missed the basement the entire act 1?

The only companion in the game that doesn't feel like a waste of class and stats, buildwise.

Lots of sneak attack damage, get him some bonus spells and extend to spam haste non stop.

4 Eldritch Scoundrel - +1 Con
5 Arcane Enforcer - Armored Mask, Dodge
6 Arcane Enforcer - Improved Unarmed Strike (Archmage Armor)
7 Arcane Enforcer - Crane Style (Two Weapon Fighting Mythic)
8 Arcane Enforcer - Dimensional Slide, +1 Dex
9 Arcane Enforcer - Accomplished Sneaker, (Full Reservoire)
10 Arcane Enforcer - Crane Wing
11 Arcane Enforcer - Crane Riposte, Wooden Flesh (Weapon Finesse Mythic)
12 Arcane Enforcer - +1 Dex, Improved Two Weapon Fighting
13 Arcane Enforcer - Greater Two Weapon Fighting
14 Arcane Enforcer - Lightning Lance, (Defensive Study)
15 Arcane Enforcer - Outflank
16 Arcane Enforcer - +1 Dex, Slippery Mind or Crippling Strike
17 Arcane Enforcer
18 Arcane Enforcer
19 Arcane Enforcer
20 Arcane Enforcer

Does everything the Vivisectionist does, but gives your More BAB, Higher HP, Better saves, 2 additional Slayer Talents to pick from, 2 more feats to pick from, 1 more Arcane Exploit to pick from, and of course you should dump all stats into Dex by this point.

I like him as an Arcane Enforcer, higher hit points still a decent amount of Sneak Attack, Supernatural abilities that ignore SR, both defensive and offensive good ref and will saves, extremely higher BAB which means more attacks per round, and higher-level two-weapon fighting feats. Even if you don't like him as a TWF you can easily switch him to Archer using Arcane Enforcer since it still gets bonus feats like a rogue, or rogue/slayer talents. Also resource management for the Arcane Enforcer is much easer than Vivisectionist, or Eldritch Scoundrel. Woljif is probably one of the most versatile characters in the game because of his high int and his high dex, there are multiple ways to build him.

Dumb wiki

does he normally lose his equipment when disappears from camp and is found with the cultists. i thought i had daggers equipped on him, but it was a while ago when he disappeared. i might have been going to get an item or something when the event suddenly played out. any insight on this would be appreciated.

follow the guide exactly when deciding if you want him to be demon or human. i picked choices entirely based on role playing and he ran away after the encounter in the abandoned building. never heard from him again. said something about his emotions and ran off to cry like a baby.

What a great wiki, listing builds that can only be possible by using mods to ignore the game mechanics. None of those builds are specific to a companion if you can just respec anyone however you want with a mod.