3,4 There's nothing to tie lenses to Http4k. You can write a custom lens implementation which unmarshalls the JSON
5 this will be tricky unless you can inject the http client manually into the connect client- then you'd provide a thin Http4k adapter wrapper - which is the pattern we use for the AwsSdkClient and AWS SDK v2z
6 see above
7 you can use an approver without the test runner wrapper. All the JsonApprovalTest does is to configure the approver and then inject it into the test case. The code is all there in the approval test module. Alternatively use OkeyDoke or JSONAssert. For the individual values - there are a couple of ways but nothing Http4k specific.