How sane can you get?

[Quantumboost]

Common Sense and Intuition as globally applied traits would likely help. They're mostly meta, but they're present as Brain Enhancements in Bio-Tech (hence, can be applied via proteus neurovirus) and would be a solid way to model having good baseline instincts and intuitions. Intuitive Mathematician would help with statistical thinking, which humans are notoriously poor at dealing with.

For psychological stability, in addition to the Fearlessness/Unfazeable, going the Eclipse Phase route and having an AI secretary-alike which also provides counseling might work. Combat Reflexes gives you a bonus against Fright Checks and means you don't "freeze" when things surprise you or go horribly wrong, and Autohypnosis gives Will bonuses, especially if you can teach a No Nuisance Rolls perk for that. The possibility of a Computer Implant with a therapy AI pre-coded seems promising for retaining and recovering mental stability; even if it's not as good as a human therapist, it's something. Dedicated Biological ones (see Pyramid 3/37, Thinking Machines) could potentially be applied via proteus neurovirus and even be hereditary.