I appreciate everyone's responses.
To clarify some obvious miscommunication here, she now wants to cycle, wants a road bike specifically, and is excited about training and achieving on it. She's a competitive and sporty person in her late 20s. It seems like a lot of people project the preferences and personalities of their partners onto mine based on the nature and tone of their advice here.
I always wanted the final call to get a bike to come from her, for her to ask to go to the bike shop, which never happened among all the other things going on, until she was recently advised that it would be a good idea to replace some high impact sports for a while. Now this was the impulse to change things up, she asked for it, hence it 'played into my hands'. I am very happy about it, and I am here to learn about how people went with getting their partners into it, making it fun, helping the passion grow, and to avoid pitfalls. This is, as was said, a bit different for everyone, but it is still good to hear about it.
She likes 'training', wants tips and information, does not care about the colour scheme of a bike, and road biking was specifically discussed with the physio/docs in this context.
We'll certainly leave no stone unturned in terms of saddles/stems etc. to refine the fit. I am a great believer in detailed bike fitting, the benefits of that are crystal clear every day I ride.