One of the first things they'll want to do is tear the old tile out, so that means removing the adapter. Now, could you mount it on the subfloor as a temporary solution? I don't know if there's enough 'slop' in the height to allow it, but it might work (the toilet would be lower, but the adapter and flange might be off relative to where the toilet sits). A little bit of dishsoap should be all you'd need to slide it back on again, and you might not need anything.
I think I'd call Toto - they could probably mail you a template. You could probably make one yourself from the existing holes before things were torn out, but a new one is probably safer.