Nothing has been decided on service patterns, yet.
AFAIK:
North Route Airport (2tph) services will route via Stalybridge - Ashton - Victoria - Ordsall Curve - Oxford Rd - Piccadilly
North Route Liverpool (1tph) services will route via Stalybridge - Ashton - Victoria - Chat Moss
North Route Leeds/Hull services (1tph) will still route via Guide Bridge, accompanied by the skip-stoppers (2tph).
Overall this will give a 6tph frequency, mix of fast/semi-fast/skip-stop.
All this is dependant on Network Rail's whim, who release the paths that the TOCs have to bid for at auction. It isn't decided by the TOCs, who are closest to the actual passenger/customer, and know best how to meet demand.
Personally, I'd like to see TPE services to stop at Ashton, as I imagine serious untapped demand. Building the M60 created a lot of car commuting from the Tameside area, some radial, orbital and trans-pennine. In a similar fashion to the Airport line, Metrolink will serve the inner suburban (Clayton - Droylsden, Droylsden - Ashton) market, whereas the train will provide the 'end-to-end' outer-suburban (Ashton - Manchester) pattern.
Another potential opportunity is to serve the growing Chester - Leeds demand with a direct service. Currently there are peak time extras between Chester and Manchester, which is proposed to be increased to an all-day service, but the ATW franchise doesn't have anymore stock (currently) which to service it. Extending the Hull - Manchester service to Chester, also retains Warrington - Leeds, as TPE services are being removed from the CLC route (mentioned above).