Hi Mike,
I'm assuming you're using the Birch release? The upcoming Cypress release may work better for you.
A few weeks ago, we merged
PR 8262 on the development version of edX. That PR and subsequent work has upgraded the version of python-social-auth, which is what actually implements the interaction with LinkedIn. I haven't checked, but it's liekly that that upgrade will have resolved the email address issue you're seeing.
As for the other issue (manually linking accounts), that was a conscious security-based decision ("feature not a bug"). However, since that lack of automatic linking is confusing, provides poor usability, and has resulted in multiple bug reports (e.g. CRI-9, ECOM-1503), we have now changed the behavior. As of pull request 8262 to which I linked above, user third party accounts will be automatically linked during sign in. As this raises some potential security implications, we have introduced other changes as well to reduce the risk - a full discussion for those interested is in the
CRI-9 ticket.
Bottom line: try the development version or the upcoming Cypress release :)
Regards,