The initial and new instance must have the same IPs (Swap an elastic ip). The new instance must have the same IP on boot. Otherwise fingerprint will be for whatever IP the instance started with.
Assuming keypair uname-ssh, To pull information from the initial instance:
scp -r -v -p -i ~/.ssh/uname-ssh.pem [email protected]:/etc/ssh/ /c/Users/uname/Desktop/foo/
scp -v -p -i ~/.ssh/uname-ssh.pem [email protected]:~/.ssh/authorized_keys /c/Users/uname/Desktop/foo/ssh/
ssh -i ~/.ssh/uname-ssh.pem [email protected] "sudo cat /etc/ssh/ssh_host_ecdsa_key" > /c/Users/uname/Desktop/foo/ssh/ssh_host_ecdsa_key &&
ssh -i ~/.ssh/uname-ssh.pem [email protected] "sudo cat /etc/ssh/ssh_host_ed25519_key" > /c/Users/uname/Desktop/foo/ssh/ssh_host_ed25519_key &&
ssh -i ~/.ssh/uname-ssh.pem [email protected] "sudo cat /etc/ssh/ssh_host_rsa_key" > /c/Users/uname/Desktop/foo/ssh/ssh_host_rsa_key &&