I've just hauled the engine and 'box lump out of my 2009 Multijet. Cam chain and rockers need fixing. The structural arms that run out to the bumpers are starting to rust an issue very visible with the engine out. But there's nothing inside the box section so a good hit with angle grinder wire brush and phosphoric acid will soon have it sorted.
Rear swing arms are available for the 4x4 but a rusty central subframe may have to be rebuilt. You'll need good welding skills and a jig will be the only way to get it aligned properly.
169 4x4 Swing arm. I can't get into ePer for the centre section and there's no images on line.
The later model 4x4 back axle just might fit. Those triangular brackets look remarkably similar to the ordinary 2WD rear axle. The basic 500 rear axle fits under 169, though it always upsets the purists and these days you can get good quality pattern parts.