Does this project have any 'business' behind it? I only see mentions of technical stuff, but there's always business (of some kind) behind. So I see the lack of 'functional' artifacts in this list. Follow my comments inline:
1- story map.
It must be seen as paramount to keep the traceability between business requirements and the stories, into which the high-level business requirements were transformed, then to functional + non-functional requirements, created from them. I'm speaking from the experience of enterprise projects (in the role of a business analyst), where it was our own pain to track the traceability (more intently than even the Customer does it), so I do believe this should be provided in the opposite direction (to outsource).
3- Technical specifications i.e. language, database, DevOps & development methodology.
Same note as for the 1st bullet: the lifeline is 'High level requirements (business) - features/stories - functional + non functional requirements. There should be functional requirements (technical specifications only support, but do not provide the functionality, which is going to solve the business requirements). This is also does not seem a task for outsourcing, because you, internally, are the generator of requirements.