OP update
Brought vehicle and replacement HCU to the “friendly” dealer in early November. They find a different code which indicates a general brake system failure. They reset the codes and it doesn’t repeat. They keep it for a week driving it all over town and return it to me without putting in the HCU.
I drive it for 350 miles or so over a few weeks and the warning lights return. Bring it back to the friendly dealer, they find the original C1478 and agree to put the HCU in. After the HCU is installed and reprogrammed, the same error message persists!
Dealer contacts Ford, omitting the fact that it’s a used HCU that has been installed, and are told to replace the brake lines (“could be restricted”). New brake lines installed, clear the codes and it test drives fine. Dealer won’t say so directly, but the original HCU is probably fine.
tl;dr - C1478/C1480 codes in 2008 Ford Escape Hybrid. Ford says replace Hydraulic Control Unit ($5,300 repair). Real reason appears to be “restricted brake line” cost of about $300. May have wasted $1,200+ on a used HCU/installation. Ford needs to change it’s procedure on this code. Cartalk member saved me $4,000+.