I would make sure that the teacher is on board with getting materials from the next level if that should become necessary (though it may well not be necessary - it depends on what's already there). Our montessori school goes all the way to 6th grade - the classroom grade groupings are pre-3 to K, 1 to 3, and 4-6. There are definite differences between the different groups in terms of what materials are available in the classroom, and corresponding presentations on the material by the teacher. It is my belief that it might be possible, in certain montessori schools, to even need a grade skip, if that would make more sense from the perspective of getting access to the materials and presentations. In our montessori school, it seems to be the case that even the regular students in K are reading at a higher level than their counterparts at the public school down the road (at least that was our experience when we switched DD7 from the other school to the montessori), so our K classrooms have a lot of stuff that the first graders would use, for example, but I know there are things in my dd's classroom that she uses that are not in my DS5s' classrooms. One of my DS5s has already managed to get at least a grade and a half ahead in math with what's in his classroom (he just turned 5, he's in the pre-K class, in the pre-3-to-K classroom), and there seems to be plenty more room for him to grow in that regard, but we'll see next year. We're fortunate that his teacher is very flexible and isn't afraid to offer presentations on more complex works even when he struggles with (or is bored by) simpler ones.
Your list looks good to me; I'm not sure how well they'll be able to group works into more complex ones - that may depend on the specific works in question. I might ask for a more complex single work at a higher "grade" level that incorporates the same information, if one exists.
What is the highest grade level in this school? That might ultimately affect the complexity of the works available. Let us know what the teacher says - I'm very interested. I'm still feeling my way around all these issues, trying to make sure our montessori school is going to continue to meet our kids' needs (it seems to be, at the moment - my biggest fear is lack of challenge via a step by step approach to getting presentations on works, and that seems to depend a lot on how flexible the individual teacher is).
(I'm still having computer troubles so I'm not quite sure what I wrote - it's hard to read over for editing!)
