I am confident that the companions have the potential to develop in different directions, and I think we got a confirmation for this in the last panel.

There was a very interesting statement from the associate lead writer (I took notes, and I hope I got it correct);

Quote
"Companion characters have the potential to grow and develop in interesting ways, and indeed the thing that makes them, that often kind of incites that within them or can urge them along the journey or block them on that journey, is you, the player, and it's very much you who is influencing how they develop and who they become."

I had assumed that this is possible, because I think that the companions are nuanced, complex and well written characters, and I am very happy that this seems to be indeed the case. I like character growth and development.
And each one of the companions seems to be at some kind of turning point in their lives, where their story could take one path or another.

There was also a statement from another writer, that it's sometimes actually better to have an argument and challenge your partner (or companion) about their way of thinking.

So yes, I think your player character can have an influence on their companions.