There is a lot of lore and myth associated with the questions here. Actually the term 'nimcha' is a misnomer as applied to most of these swords, though it has become a popularly used classification for this spectrum of sabers from the Maghreb (Morocco and Algeria). The term loosely translates to short sword in Arabian, which as can be seen, these swords typically are not.
These are typically called sa'if in Arabic and local parlances, but collectors sometimes regard these as Moroccan sa'if, though they were of course widely used in Algeria as well. Through the trade networks and entrepots in these areas, many blades came in, mostly German of course. There were cases for some French and Italian on incidental basis, and as I have noted, also seen on occasion are the "Spanish motto" types (draw me not without reason etc). What is most odd is that these are double edged and straight, hardly the ideal 'saber' blade for the type of use in most Arabian contexts.
These are typically regarded as Solingen made for the Spanish colonies in New Spain (now Mexico) however many were made in Toledo after 1770s.
The ANDREA FERARA blades are typically Solingen made for Scotland in the 17th-early 18th c. but these often made it into England as well. There was notable trade between England and Morocco/Algeria in the 17th century and there are instances of English merchants wearing these 'nimchas'.
The Andrea Ferara thing regards an actual swordsmith from Belluno in Italy of the 16th century, who seems to have become a virtual legend mostly from the romanticism of Sir Walter Scott, but the blades were indeed favored by the Scots before that. The term ferrara is of course Latin for iron, and the Andrea, Italian for Andrew, the Patron Saint of Scotland, with the name or term meaning true or good, thus a high quality blade. Obviously conveniently construed, as a colorful Scottish trait.
Many European marks were imitated in degree in native contexts, and were seen in league with symbols or having meanings aligned with the superstitions, traditions and folk religion of the regions. In many cases these were seen as talismanic, or imbuements of power and strength.
The import of trade blades into North Africa has been noted into the early 19th century, however this is hardly that recent a phenomenon, and likely blades came in to some degree centuries before. There were once blades from as early as the Crusades circulating through Saharan trade routes, one in particular I recall from 16th c. but these have long since been collected away. As I mentioned earlier, the landmark article by Dr. Briggs in 1965 has been a cornerstone for the daunting study of European blade marks and served well as a benchmark for these studies since.
Your questions are well placed, and while I have been at this 'a minute or two'
and like most of us, am very much still learning, which for me is a happy thing!