Difficult as it may supposedly be to make Spadina accessible (certainly I don't think it's any more difficult than many of the other stations), I don't believe the AODA would be satisfied by telling patrons to ride the 127 from Kendal/Lowther to the Bloor side of the station and transfer at St George. If that would work, they wouldn't be installing elevators at 90% of the stations that they are.
Yes, they will need to put in elevators at the south end of the Line 1 platform for people to get up to the hallway that leads to Line 2. If there is private property above where they need to excavate and there is no feasible alternative to place the elevators a few metres in another direction, then they will likely need to expropriate.
I don't know if they would be required to also put elevators at the Kendal Rd entrance at the north end of the platform; I'm assuming not, and that the AODA would be satisfied by elevators that go to the hallway that leads to Line 2 and the accessible exit to Bloor St. In fact I'd say that the opposite--having elevators to Kendal and not to the hallway to Line 2--may not be considered accessible, because there is likely far more passenger demand for line 2/the 510/bloor st. and not having an accessible route there cannot be saved by having one to a minor sidestreet well north of those other points of interest.