You may combine the tool and vehicle proficiencies of both of your Avatars, allowing both the same proficiencies. Although, they still use different ability scores for those skills. Additionally, you gain proficiency in the tools used to heal or repair your Avatars. Humans use Healers Kits, Med Kits and Herbalism Kits. Androids and Constructs use Hacker's Tools, Electrician's Tools, and Mechanic's Tools. And Undead use Poisoner's Kits, and Brewer's Tools.
Alternatively, you may select one other character to teach and learn from. Both characters gain proficiency in any tool or vehicle that one of them already has proficiency with. This teaching must be done during a week long downtime activity, or may be completed after a month of travel or light adventuring. And you must have access to said tools or vehicles during this time.