What you are asking your school to do is change the methodology of their program. You have no legal right to do that. Your daughter has a right to accommodation. You do not have the right to dictate methododolgy. The whole philosophy of bi-bi is founded on keeping 2 languages separate.
Any bi-bi program is appropriate for CI users. What is not appropriate for a bi-bi classroom is bringing AVT into a classroom that is taught using ASL. Having a CI is not a disability. Therefore, you cannot walk into a program designed to be bi-bi and for deaf children and demand that your child be given oral instruction because she has a CI. The accomodation for her being deaf has already been made. That is the disability that qualifies her for accommodation. If you don't want her in a classroom that uses sign as the language of instruction, then, quite simply, don't put her in one. Put her in a program that uses speech as the language of instruction.
And self contained CI programs within a deaf school are the same as a self contained program for deaf students in a mainstream school. They function differently than the rest of the school functions. And those self contained programs are created so that those students whose parent want a different methodology than the school's primary methodology have a separate classroom in which to accomplish that.