The instructions at the time of the Integrated Rail Plan were pretty clear; all existing blight claims would continue to be valid in accordance with the existing legislation. The company were to keep the land and the relevant safeguarding would remain. In other words for the purposes of compensation and ownership it's as if the scheme is still going ahead. It will probably stay that way for a long while yet as alluded to by snowball.
In any case, with the the quickest progress, the authorisation for the Crewe - Manchester route may be in place by the time of the next General Election. By then, matters will be clearer on what the elements of NPR that will actually be constructed under the IRP will look like, hopefully having been consulted on. This means that there will be the Birmingham - East Midlands section, and the various NPR sections, plus the possibility of other bits and bobs that haven't yet been authorised that could be tacked on, such as work in Merseyside. These may be gathered together in the form of a new (rather long) hybrid bill, split into two hybrid bills, or use one or more of applications for Devolopment Consent Orders in addition to a hybrid bill. Only once we have reached that point would the legislative timeline for the Eastern Leg have come into view. This will probably not be until the second half of 2024 at the earliest, and may be 2025. By then a new government with very different priorities may be in power and may well choose to add back all of the cut elements of HS2 Eastern Leg. There is hope yet.
Of course, by exactly the same token, if they wanted to build everything in the IRP and also the Eastern Leg in full, there is a risk that an incoming government in 2024 could run out of time to get everything consulted on, budgeted in terms of the capital expenditure, and through Parliament in time for the end of the their own tenure. This could lead to further difficult decisions, such as breaking the Eastern Leg into further constituent parts. If the new government is not a continuity with the current one, it will have one almighty legislative agenda to try and get through. HS2 is never going to be higher priority than election systems, constitutional questions, welfare and tax reform, employment rights or energy policy. There are probably more things you can add to that list.