It sounds to me like the owner wants to do some fairly major works, which include changes to the common property, and likely also taking over common property. That is very complex and if it did go to the owners for approval there is a wide range of issues that would have to be dealt with, which could include things like the owner paying the OC for taking over common property, allocation of liability, indemnities etc.
There is nothing wrong with sounding out the Committee about their likely position on something like that, but if the works involve changes to and/or taking over common property, then the Committee doesn’t have the power to approve those works.
What you could say to the owner is they should provide an overview document setting out what they want to do as a starting point – that is the beginning of the process. The Committee is not in a position to approve anything at this stage. I know a building where a lot owner did something similar, and it took a long time for him to obtain approval, i.e. a couple of years.