I know it's in the Sun, but looking at the proposed site of the new stadium they would clearly still need to find somewhere else to play during the building phase as a substantial part of Sid James obviously needs to be demolished. Probably a minimum of two full seasons as well.
I can't see Northumbria Police ever agreeing to letting them play at the Sol given the havoc this would cause in Sunderland town centre every other week for two years, so realistically that leaves them with Newcastle Falcons - 11k capacity, Gateshead Stadium - 11k capacity or Darlington arena - 25k capacity. The only other option is to go completely off piste and go with something like Murrayfield which might not be as fanciful as it sounds.
They seem to be looking to make this whole issue as difficult as possible for themselves.