Yes-there are no guarantees between weather or unforeseen mechanical issues.
At just under 1000 nm, you would need 4(+/-) pilots and most likely an overnight foster. So in your request you would need to specify that those involved are able to administer the insulin.
I would also suggest contacting PAART http://pittrescue.org
since they do some flights for PNP and may have some advice regarding a transport of this length.
I do hope you can make this happen. I have seen many times where pilots are so willing to go that extra mile to help "special" pets get home.