Cleaning Val Protocol - Micro Lab

I need to set up a cleaning validation protocol (CVP) for an analytical microbiology lab in a small company. Because this is not a CVP for glassware or for production, I am having difficulty in getting relevant guidance (and it’s my first time).

I have included cleaning procedure, sampling procedure, analytical testing procedure, acceptance cleaning limits (USP), and criteria for validation. I also am planning on providing intentional contamination as a worst case challenge. I need help with some details, however.

• We are using Virox for cleaning (stabilized H2O2). Do I need to show that it is completely removed by the cleaning rinse (TOC would be my choice)? Do we still need to clean with more than one agent (alternating to prevent microbial resistance)?
• Our swab areas are 4 inch square, but I seem to recall a mention somewhere that for validation, 2ft x2ft areas (8ft x8ft for floors and walls) is preferred. Is that necessary, and if so, how logistically is it accomplished?
• Our positive challenge would be a mixture of Escherichia coli, Staphylococcus aureus, and Bacillus subtilis in solution at 5,000 organisms/0.5ml/4 sq in dried on the test surface (200x the maximum acceptance limit of 25 cfu/contact plate for one room and 1000x the limit for the sterile room). Is this a reasonable challenge?

I have included as much detail as possible in the questions, because I may not have thought of all the right questions to ask. Your responses will be greatly appreciated.