Lease department of the dealership where I worked had a fleet of Astro vans out and when they were taken out of service , 1/2 of them needed those lines/hoses replaced .
I had to have a oil feed line for the air compressor on my Cat made up at a local truck repair shop . 800 degree and 500 Psi was the spec on the hose they used , fittings and all was within $5 of ordering the part from Cat, ready in an hour.
I hope you can find the same service and availability close to you.
Can't remember any problems removing the lines from the engine on the Astro vans , if memory serves , rad end was a tight squeeze. I'll scratch my head while looking at the diagram again.
EDIT: If possible can you post a picture of the lines at the connection to the motor , I think there is a spring clip that holds the fitting and line together , but I'm not positive.