Can sending the same plaintext twice, each encrypted with different key and IV, weaken the encryption?
No, it would not compromise the strength of the encryption (assuming that you didn't use a key that the attacker could guess).

We can take it much further; you could give the attacker a billion encrypted messages, all being encryptions of the same plaintext.  It wouldn't matter if you told the attacker what IVs you used (or AADs, should you decide to use them), or if you used the same keys or different ones.  As long as:


You didn't pick a key that the attacker could guess; for example, you picked the keys randomly
You didn't reuse a (key, IV) pair (which in this specific case would matter if the two messages had different AADs, but it's always a good thing to remember when you're using GCM)


Then the security of the system is not weakened; the attacker would have no information (other than length) of the encrypted message, nor could he generate (with nontrivial probability) another encrypted message that would be accepted by the decryption process.