2018 Versa Note driven w/o CVT fluid less than 50 miles

My girlfriend recently began noticing erratic shifting and CVT jutter when accelerating from a stop in her Versa. She told me about this roughly 2 days after it began, and she drives about 5 miles round trip to work 5 days a week.

I called the Nissan dealership because I knew there was a recall / warranty extension for the CVT. I asked if I should check the fluid levels before I brought it in, but they instructed me not to do anything, because it was just out of warranty and they didn't want me to do anything that might jeopardize coverage.

(Warranty extension expired December of 2024 at 84,000 mi. The vehicle has 84,622 miles.)

The dealership just called me back to tell me that the CVT lines are rusted out, and the transmission is almost completely out of fluid. They want want over $650 to replace the lines and refill the transmission with fluid. I can get the lines and genuine fluid for about $150.

The service manager is pressuring me to let them fix the lines protect warranty coverage. If there are still issues after the lines are replaced, she is worried that it may jeopardize warranty coverage if the lines were not replaced by the dealer. She did relent towards the end of our call, and told me to bring her receipts showing I used genuine Nissan parts and fluid.

1. As long as I use genuine Nissan parts and fluid, will the warranty coverage be affected?
2. Given that the transmission was driven with very low fluid and the dealership knows, wouldn't the warranty already be voided?
3. Ignoring 1 and 2, how likely is Nissan to approve claims like this when the vehicle is just outside the coverage window?