There is no one development process that fits all; Scrum, Prince, Lean,
Extreme and whatever the current fashion is all have their place and can
work but it's typically a hybrid that works best for you now. Things
will change over time and the next team, platform, role or project may
require an entirely different approach. Having an adaptable approach
will make things smoother for you.
Consider more formal methods for the meta-project such as milestone
structure and operate an agile process within those. Consider "beach
head" style changes to your production pipeline by introducing the new
process to aspects of your project, e.g., introduce Scrum on your AI
team before you unleash it.
This way, you'll get to iron out the bugs and if things go well then at
least you'll have trusted people on board when it comes to making the
broader change.
Consider running agile process for the highly creative periods such as
pre-production and concept and more formal methods for the middle bit
where you're largely implementing your design.
Whatever it is, think about the implications on the production and
people involved as they're both intrinsically linked.