I also wonder why TPE are required/allowed to run 2 Newcastle services per hour when the core route is overcrowded a lot of the time The extra 3 coaches per hour to Newcastle are not going to have a huge impact given the number of alternative services from York to Newcastle where as strengthening one of the airport York services from 3 to 6 carriages would make a difference.
It's not about NCL.
2tph from LIV and 2tph from MIA require four destinations. The train planners dream is to have a nice even distribution of services Manchester > Leeds > York. You
could send one to MBR, one to SCA, one to NCL and terminate one at YRK, but if you can get the path to NCL and therefore call at some other places on the way, why wouldn't you?
In theory, from December, once the Cl 802s are introduced, the 125mph running will allow the intermediate calls between YRK and NCL to transfer onto one service without delaying the ECML. This then allows a service to run fast to NCL before continuing to EDB.
It also puzzles me that given First also run the major bus route through Mossley that First TPE never arrange ticket acceptance with First Manchester.
Rail and Bus are an interesting mix. TOCs tend to have varying agreements regarding ticket acceptance. Some are a bit "you scratch our back and we'll scratch yours" - i.e. TPE/Northern and Metrolink, whereas some need actual written contractual deals - mainly so the TOC has somebody to hold responsible if anything goes wrong. When it comes to rail replacement road transport, it is provided by a dedicated supplier as most journeys are more than 10 minutes, so buses are not ideal for both comfort and speed. A TOC like TPE deal with a central control room for their supplier who will then deploy their own coordinators and order relevant transport from local companies.