The old boiler from the Alco certainly was in Minffordd yard, probably it's still there. I was heavily involved with the boiler "overhaul" of the French example. It only required a new boiler barrel, front tubeplate, backhead, throatplate, and outer firebox sides, and the firebox dismantling, repairing and re-riveting... We costed a new one, it came out cheaper, but the owners wanted that one repaired, so we did. I doubt that the one in Minffordd yard will be in any better condition. They were made from very thin plate, as is Yank practice, and the tin worm hadn't been kind. They weren't particularly well made when new either - the stay misalignment between the box and backhead is the worst I've ever seen on a boiler still as it left the manufacturer. If it was to be rebuilt to original, I'm fairly sure it would end up with most of a new boiler, possibly with some strategic bits salvaged from the old boiler(s).