Lite Core is the underlying implementation of the upcoming 2.0 version of Couchbase Lite. It's still under development. The intention is to have a common core, with platform and language specific bindings on top.
There is currently no Go implementation I'm aware of.
cgo does look like an option. Given the goal of Lite Core being the underlying implementation for all platforms, this seems on its face like a reasonable approach.
If you're interested, there's a GitHub account for community projects at https://github.com/couchbaselabs. If you work on this, it would be great to have it included there.
To see an example of platform integration, take a look at https://github.com/couchbase/couchbase-lite-ios/tree/feature/2.0