As I read through, having a similar condition in that I cannot remove the 4500 function id references, it doesn't seem as though this ever was resolved. In my case, I see that the issue is with two partition functions and two schema functions being attached to the same table and that table is partitioned. I think that if I can remove the partition from the table, I will be able to drop the partition scheme and partition function. The only issue I am running into going forward is that it is a bit awkward to remove the partition.
If the partition is removed, is it necessary to move the data to a new table or is it simply a matter of merging all the data back into the primary partition?