There is nothing wrong with riding a touring bike in brevets or randonnees.
My original bike for those types of ride, plus commuting and touring, was a Fuji Touring, then followed that with something recovered as a rubbish dump recovery that became my fixed gear.
It's only comparatively recently that I have used a CF Merlin (which I don't for randonnees anymore) and a Hasa Ti bike that is closer to touring specifics than an outright road bike... and it still has a CF fork.
As to the specs of the frames in terms of steering angles... can't say. The earlier bikes have forks that are nicely curved, but the later ones have forks that are straighter and rely on the join out of the steering tube to create angle for feel and handling.
So long as the bikes feel comfortable to ride and steer when tested, I am happy to ride long distances on them (of course, refer to my comments in another thread about Brooks saddles, which all these are equipped with).
The Fuji has now done more than 60,000km of my riding and sits half retired now, but is still comfortable enough for me to ride occasionally. The Hasa Ti is my favourite for randonneuring.
My latest touring bike is the English Thorn Club Tour which has a traditional lightish steel frame, and it has done a few shortish randonnees as well, and it is something I enjoy riding, even in my current recovery period. And I am really looking forward to getting back on to the fixed gear again (which incidentally was a FG touring bike after PBP 2007).