It is not very much, I can contribute to the MERAL question:

I also own a Meral with Camus Carbone mangane steel tubing and I know of a couple of further bikes with this frame. Originally, these bikes have been equipped with Shimano 600 parts.

I also own a Meral touring bike and have seen some further Merals, race bikes with different tubing and equipment. Also I have seen very nice made randonneurs.

Merals have been sold in the 1980's in Germany and until the late 1990's I have seen a couple of NOS Merals at a bike store.

The relative new (french) Bicycle manufacturer Cyfac states, they formerly have produced Meral.

Regards