Where will it call between Liverpool and Manchester (I seem to remember Huyton, in which case it would probably be the fastest train calling there?).
Possibly only Huyton.
I wouldn't be surprised if it's main use was people turning up at Lime St/Victoria and piling on the next 2 car train to Manchester/Liverpool rather than waiting for the TPE services.
Depends on timings and paths. If the Northern Connect departs Lime Street 5 minutes after the TPE Edinburgh via York service then it won't have many Manchester passengers unless Arriva introduce some cheap Northern only tickets.