My best guess: The ICE Blackwing will not get the revised fascia or interior and ends with the '24 MY. It will return as an Ultium based rig and as an interim step Spring Mountain installs generators powered by excess LT4 inventory. But seriously, we're talking Nevada here, not California, they can have a charging infrastructure installed in a month.
I see no business case for the CT4/5 soldiering on for years to come. They killed the Camaro and it sold about the same number of units (24k) as the 4/5 combined in 2022 (good car bad car). At a few thousand a year, the BW niche is not really contributing to the EV transition like you can argue with the ICE Mustang and the Mach E. The refreshed ICE 4/5 makes its a few additional years to try to bridge to the 2030 "all electric" vision.