I've switched seats many times from both regular cab and extracab. On the split bench or buckets, the inner bracket is different due to different hump in floor. I've got some brackets still if anybody needs them. I'd have to verify which cab config they are from.
Wife here did nearly the same thing, this summer, picked up an 05 ESV Platinum for 1/2 of loan, with 50K on the ticker, said she wasn't gonna drive no stinkin diesel! I have to admit, it's an awful nice vehicle, tows well for a 1/2 ton, with the air ride and the 6.0.
With that many miles, don't know how much rust you would have, but here in MI, the factory fittings to the block would be toast as well and need to be changed. And if you are at that point, might as well do some real plumbing with mechanical fasteners, ie npt fitting into block, then elbow into...
In some ways I agree with Slim, if you want to catch it all, easier all lumped together. IE for the regular visitor that keeps up with everything.
If you want to only search specific things, easier if broken up in sections.
Yes, as the 6.2/6.5 ends up being the 88-2000 year trucks, I think engine/body/electrical/etc should all be subforums if it is going to be broken down.