Actually, I'm taking a left turn from the movie plot after the cave in Afghanistan. Partially because I want to avoid rehashing the movie plot as much as possible. And partially because the only person I could think of to slot in "long-time friend of Jacob Carter who helps run the company" is Hammond, and oh my god, I cannot write Hammond as Stane. :P

So, the Stane-like character is currently "Stane-minus-betrayal", which leaves "cool mentor figure who may or may not show up".