Re the JV, ALCOA hold the whip handle, understandably I expect...

Re the JV, ALCOA hold the whip handle, understandably I expect they will extract the very best deal obo their shareholders, as they should. They didn't become such a successful multinational behemoth by giving away good deals.
FYIs HPA product will be sold with ALCOAs support and financial backing into its high value market. So it's FYI that will benefit substantially from ALCOAs support and entre' to its massive network of end user/consumers eg TESLAs.
It's ALCOA that will call the tune.
Sure, FYI can expect a lot better than cost plus, it's not in ALCOAs interest to hold FYI back. ALCOA is the big boy in the deal and can make/break smaller companies. We could learn a lot by examining their treatment and success of similar jv's (I haven't looked).
So don't expect largess from ALCOA.

[As an aside - Shell used to operate a 'Step' program that engaged in JVs with smaller oil related companies to foster them with the (unstated) aim of mentoring the CEOs and ultimately buying out the most successful JVs to poach the CEO. They were willing to pay a good price to capture the CEO (win/win) and his/her upcoming company. A successful strategy for Shell in finding lean mean hungry candidate CEOs for Shell. ALCOA is a similar size company with similar succession issues through the top ranks. Just a thought, it doesn't necessarily follow that's what they're up to]