For sterile products, is it acceptable to manufacture the small scale batches in a nonsterile facility and allow variance from sterility and particulate criteria?

No. To be consistent with ICH Q1A(R2), sterile product small scale batches
should be representative of the manufacturing processes to be applied to a full
production scale batch, and therefore should not be manufactured in a
nonsterile facility. Sterility is a critical quality attribute (CQA) for sterile
products.