If I inquire about a holy person not mentioned in the Satcharitra, can you use its general teachings to provide a relevant answer instead of just saying they're not there?

Yes, that is the ideal approach, which is grounded in the teachings of the book itself. Chapter 19 provides a strong foundation for this by advising that when a 'wave of good thoughts arises, one should certainly nurture it.' Your inquiry about a holy person is precisely such a thought. The text promises that by 'nourishing that same thought, great satisfaction will be felt.' Furthermore, it highlights the principle from the Bhagavad Gita that Govinda provides for the security of 'those who think of Me with undivided attention.' Thus, even if a name is absent, your devotional thought can be supported and enriched by these universal teachings on faith and surrender.