I have been wondering of what kind of class you would pick if you made a tinker or engineer. It would be good to know that before an engineer is made. If you may put a post on this topic I would enjoy it.
What class would be an engineer or tinker in game?
It could practically be any class. Rogue probably, but I could see cleric (of Gond), wizard, bard, or fighter working as well (or a multiclass).
The key thing is to have a lot of Craft Trap (which represents engineering) and Lore, and likely also Spellcraft if the character wants to understand magic (and lots of the "tinkering" in EfU is magical as well as mechanical).