Mojak, the question of heat treating the blade should really be decided as to whether the blade is warped. Hold the blade with the spine down and the tip of the blade at arm's length and pointed towards your eyes. If the blade appears really warped, then that's a knife that likely needs to be re-tempered. Compare that blade with others, to decide if it needs to be straightened.
If so, check out this thread: http://www.bladeforums.com/forums/showthread.php/838681-Straighten-During-The-Temper?highlight=Marchand+warp+blade
Keep in mind that you will need to remove the rivets and the old scales and replace the rivets and maybe the scales as well. Keep in mind that with that old Wustie, with its forged bolster, the scales will likely have a tapering thickness that you need to compensate for.
If it's not otherwise warped, then don't mess with it.
I agree with MillionsKnives that you need to work on the bolsters on each side of the blade. At the very least, they need to flattened out and not convex. Ideally, the bolsters should be reduced as much as possible. And as MillionsKnives mentioned, a Dremmel tool (or some copycat tool like it) is best. I use one from Harbor Freight Tools as my cheapest alternative. Just be sure to use proper safety gear, including eye protection, ear protection and something to minimize metallic dust inhalation.
Keep tabs on how much heat is being generated during the grinding process, especially when you get out near the edge. Ease off if it starts getting too hot to touch. But, you should be Okay concerning the tempering of the steel if you are only grinding away the bolster and not the edge.
From this point on, no motor tools. It's bench stones only. You don't want to mess with the heat tempering of the metal of the blade along or near the edge.
For the tip, work from the spine side. If you can support both sides of the edge, then you can reduce the risk of bending the tip.
Next, for the edge near the heel, where there's a concave profile to the edge, the only solution is to work on removing a part of the edge back to the heel, so that you can have either a straight or slightly convex edge profile running back to the heel.
Now, feel the thickness of the blade behind the edge. If it feels too thick, then you need to thin the blade behind the edge.
Then put on your edge.
For the slicer, then most of what applied to the Wustie applies to that knife. What concerns me is that you have quite a long stretch of concave edge profile.
For the cimeter, the blade looks in very good condition. The one primary issue there is the handle and the extent of the connection between the blade and the handle at the heel. As a footnote, I just received this week a 300 mm (new-old-stock) carbon steel Gustav Emil Ern cimeter, so I am examining that handle to see what might be needed. And what concerns me is that my cimeter has significant fit issues and wide gaps at the transition between the handle and the blade. Also, cimeters, breaking knives and boning knives traditionally had fairly crude handles. You may need to fabricate a new handle (consider laminations, so that you can fit the handle to match the bevels of the blade).
You may also want to look at re-configuring the follow-through of the edge of the blade, so that there is a clear follow-through of the edge all the way back to the heel. Also, see if the tail-end part of the edge running back to the heel, which is traditionally hidden by the handle, needs to be re-profiled to present a straight run-through of the edge back to the heel.
Hope that helps.
Edited by Galley Swiller - 12/28/15 at 9:22pm