2. Yes, if I don't remember something about someone, I'll look them up by name and read the notes.
It's not tedious for me as I have less than 100 contacts that I manage this way.
To give you a description of how it's layed out, top level is the Notebook, which is titled "people". This is the file in which I store all data. Then I have the tree structure with H1 groups, aka Family, Friends, Workplaces, Enemies ;), etc. Under that I have my H2, which are their names, or in the case of Workplaces I have the company names I used to work at, then the H3 with names. Under each name I have a free text filed where I type everything, this would be my "note" for that person. But if I wanted to I could nest even more headers and add more structure, it's just that I don't feel the need to. The app lets me add tags and arbitrary key value metadata, but it seems overkill for me.
I also use this app to manage other things, like workout schedule, a backlog of FOSS ideas, shopping, interviewing, investing, and others, both high level and low level. It's quite flexible.