One piece of advice that is often offered by creative writing books and courses is to nail your characters before you begin writing. Work out their name, their age, how they look, where they were born, what their attitude is to marriage, etc, etc. The list is endless. For a long time, I followed this advice and attempted to write my characters into the details and personalities that I had so carefully written down and crafted beforehand. Do you know what happened for ninety nine per cent of the time? I wrote cardboard cutout characters who fell apart under the rain of conflict and time.
I now understand that I was taking the 'get to know your character' advice too literally or too naively at least. What the advice should be is 'work out the details of your character's life that you need to begin writing'. The difference between this and the 'nailing of characters' is that with my version, there is room for your characters to develop and grow as you the writer gets to know them.
As a writer of murder mystery plays, I start with a number of set details. There is a crime, a victim (usually somebody altogether awful whom the other characters have reason to dislike) and a guilty party. I then have to work out why anyone would want to commit the crime. What are my suspects' motives? I then have to work a storyline that reveals or at least hints at these motives and places the suspects in the right place to have committed (or not committed) the crime. These are definites that have to be included. My characters begin with a name and a motive, possibly a job or other life detail such as married, divorced, elderly, young. It is with the actual writing of the play that the characters show me their voices and therefore their personalities.
In the novel that I'm working on, the one character whom I thought I always had nailed, Isabelle has surprised me by how strong and feisty she is. She is still driven by the same fear that I always knew she would be. That has never changed. However she has revealed herself to be not only a survivor but a fighter. I didn't see that in her until she'd developed through several chapters.
Similarly, a character who started out as my villain's sidekick has developed new levels, or should I say depths. He has a distaste, if not a hatred, for women that I never knew about before I started writing this novel. He has engineered the villain's destiny rather than the other way around and he still has plans to be rid of his master. I never saw that coming in the original story plan.
By all means, sort out the details of your character's lives. Get a taste of who they are. Live with them for a while. Leave space though for your creations to grow not only into the characters you had envisaged but beyond that in ways that may surprise you but which will ultimately reveal their truth.