No. Federal FOIA addresses reasonably segregable nonexempt portions, but an agency may conclude that separation is not reasonably possible. Review the specific explanation and available appeal process.
Generally, requests to state and local agencies are governed by applicable state law, not federal FOIA. Identify the relevant jurisdiction before using federal terminology.
Yes. A focused request for clarification can ask whether partial release was considered. Follow the determination's appeal instructions independently of that clarification.
No. Record the visible text and cited exemption; identify unknown content as unknown. A redaction is not proof of a particular fact or allegation.
Do not assume it does. Use the actual determination and agency instructions to track the deadline, and obtain legal advice where needed.