One way to accomplish this would be to walk from Ferrol along the camino until Hospital de Bruma, then go off camino 2km to the bus stop in Meson do Vento and take the bus to Coruña then walk again from there. Doing it that way, you'd be on the "official" route the entire time (well, except the diversion to Meson do Vento), and experience the entire English route.
To walk directly from Ferrol to Coruña would mean walking along the camino until just after Miño, then cutting across on the Puente de O Pedrido then making your way through Oleiros, which doesn't have any actual 'route' to follow, so might be a challenge. There would be local city buses in the area as an option (rome2rio.com will help figure that out if you wanted to).
The only issue is that doing either of these would mean your 'official' starting point would be Coruña, which doesn't qualify for a Compostela, if that's important to either of you. (Recent changes to the Compostela rules say that people who live in Coruña can qualify for a Compostela, but I don't have the impression that you guys live there.)
How lucky to be from A Coruña! It's my favorite city in Galicia! Buen Camino to you guys!