Hi Anastasia,
Here is a link to the post I talked about above:
It is just an encouragement to experiment with Coda. There are no right or wrong ways to do things, although sometimes some ways may be better. I have one or two very early docs that I look back and chuckle, but what I did worked even If I would build it very differently now.
But that was a very simple doc. My big doc I have re-invented several times over the years. EVERY TIME I have moved more information that used to be in different docs, into the main doc.
As for your specific comments on the People database/table and the contact details. I would try and keep it all in a single table, in a single doc. If there is a need to store confidential information, then add that confidential info in a cross doc.
P