This is a good question. The Oriental Land Company which owns Tokyo Disney Resort has deep pockets, and has been known to reroute the Monorail (such as when adding DisneySea). Keep in mind that the Monorail is technically part of the Tokyo Metro.I have an issue and question about this challenge.
Is the monorail lines suppose to stay open. It’s the only means to half of the hotels and DisneySea from the Disneyland Train station and is physically a part of the Ikspiari
I would say keep in mind how your project will impact the resort during construction. If you must first reroute the Monorail away from Ikspiari to have a cleaner slate, that is a valid option. What you’ve proposed to your team, @Voxel, also sounds like a realistic approach.