Ultimately they have to do some type of work to make the OT available at today’s standards since the 1080p master is horridly outdated and has been scribbled over with crayons ad nauseam.
The easiest thing to do would be to work with the original unaltered negative and start from scratch in 4K. Disney has done well so far in restoring live action without tampering. The issue is cost and contractual negotiations and convincing the brass that it is cost effective.