A good LBS will help her tweak the components and swap out parts. I put WSD saddle and handlebars on my bike for comfort, size, and ease of reaching the brifters from the drops. I only had to pay the difference if any parts were more expensive than stock. A small stem change will also be less of a change in reach than the WSD top tube if needed. So, if she doesn't like the WSD geometry but has trouble with some of the other components, that's not a big deal. It mostly depends on her effective torso length (actual torso length, arm reach, lower back flexibility, etc.).

If she really wants to train for triathlons, she may want to look into some of the TT/Tri bikes, maybe with removable aerobars or two sets of handlebars, since the geometry and aerodynamics of these bikes are often different from standard road bikes.