Does Amazon link accounts?

Does Amazon look at the history on my accounts in other countries (Amazon.com; Amazon.co.uk; Amazon.fr) when I'm contacting them for a refund?

Or could I easily do, say, 2 refunds on US Amazon, 2 refunds on British Amazon, 2 on French and Italian?

They aren't linked, so what you're planning should be possible.

No not link but be safe anyway

The accounts are linked, in fact when you try to log-in with the same email/password on different Amazon's it let you log-in.
But, as far as I know, the rep doesn't see the order history if the CIS doesn't get involved.