My own plotting comment is here for reference. But I'd very much like CR with Geralt (white-haired warriors have to get along, right?), and could probably play something out with any of those options (she'll be curious about the herbs, and would be interested in non-poisonous culinary ones; has domestic and fairly simple daydreams also; and could team up with him as mutual trainers.

Magnus would make for interesting CR with her as well, since she has a love-hate relationship with magic in general. I'm canon-blind to him too, but based on the above, he seems friendly (and completely opposite).

Willing to plot with my other characters as well if anything in particular hooks your interest!