urgent request - AWS and GitHub Contractor Isolation

Hi! I run an early-stage AI SaaS company (prod on AWS bedrock S3; code on GitHub). I'm about to bring on external engineering contractors for the first time, and before they start I want proper technical controls so they can build against code and masked data but can never reach production or customer data. I'd love to hire you for a few hours. If you could walk me through the expected controls, I can then figure out how to properly implement it. If you're available, I'd love to chat ASAP since our engineering contractors are waiting on this. I can meet most times tomorrow July 8th. Relevant things I'm thinking about: IAM, least-privilege permission sets scoped to dev/staging, SCIM provisioning, JIT/time-bound elevation for rare prod access, likely multi-account separation via AWS Organizations + SCPs, locking RDS/S3/Secrets Manager behind boundaries, and GitHub controls.