I know there is various opinions in Spanish guns and the quality of the Steel used and/or hardening processes. Many opinions concerning this are not good.

I see Belgium guns that appear to be very nice from makers such as Francotte, Bury, Defournay, Lebeau-Courally, etc. Have there been concerns about the Steel or hardening of parts in the better known Belgium Makers? Seems like an alternative to Spanish guns albeit at a higher price. Heck of a lot more reasonable in price as compared to English guns though.

It depends on the original quality and price point. Some are excellent, but at the other end of the price scale I remember before such things were prohibited a self-opening Belgian.410 shot pistol.
It wasn’t meant to self open but it did when you fired it!

The problem with currrent Belgian guns is that they're no longer in the business of turning out large numbers of relatively inexpensive guns. The reason Browning switched from Belgian-made Superposeds to Japanese-made Citoris: price. As prices for the Francottes they imported continued to rise, Abercrombie & Fitch began importing Italian-made Zoli-Rizzini doubles. Decent enough guns, but giving their customers a less expensive option.

You can find pretty good deals on Belgian doubles with lesser names than those listed above. Anything relatively modern from Belgium, which would start with pretty much any gun from the between the wars years up to the present, is likely to be pretty solid and reliable. But not necessarily all that much cheaper than a Brit double. Right now, if you're looking for a 12ga boxlock, you can find some really good values in used British doubles. As a percentage of their overall production, the Belgians made more smallbores than the Brits did. In that area, you may come out ahead looking at guns from Belgium.

Just buy American and be done with it.