There are a lot of questions here, but I will answer what I can. I am currently working on a project about non-Iberians in the Spanish Caribbean during the 1500s. It can get complicated. I would first like to mention that North America as a term for colonization can include multiple ethnic groups and nationalities. For example, if we were to just talk about the colonial history of the United States, we would have to start with the Spanish founding of St. Augustine as a response to French settlement efforts in the mid 1500s. We could then discuss Jamestown, New England colonization by English, Dutch, and Swedish settlers, French settlers in the far north, Russian expansion into the Pacific Northwest, and Spanish missionary efforts in the Southwest and up the California coast. This also ignores that fact that just because a ship left London, Lisbon, or Sevilla it does not mean that the ship's crew and passengers are English, Portuguese, or Spanish, respectively. Thinking of conquistadores as Spanish, for example, is problematic in that many settlers and soldiers-of-fortune sailing under the authority of the Spanish Crown did not identify themselves as Spanish or were not from Iberia at all. The first Irish parish priest in what is now the US was not a settler to New England or Maryland in the late 1600s, but one Ricardo Arturo living in St. Augustine in the 1500s. (See Francis and others in the forthcoming La Florida Project)I say this to preface with the warning that settlers in the 1500s were much more mobile that we give them credit for. Ethnicities and nationalities as we know them today do not translate very well to sixteenth-century thinking and understanding about identity.

So, to answer your question: Yes, other Europeans were settling in Mesoamerica and South America in patterns similar to the diverse settlement of Upper North America. Some regions from Iberia have heavier settlement patterns than others due to geographic location to Iberian port cities (e.g. Andalucia), economic development of those regions (e.g. Extremadura), or some foreign areas because of merchant activity in port cities in Iberia (e.g. Italians, Portuguese, Germans). As an aside, there is no such place as Italy or Germany in the time period I am talking about, but Iberians often identified other Europeans from outside region based on language, i.e. Alemanes. Let's look at the general makeup of conquest and settlement expeditions to these areas:

I tried to get the bullet points effect to work, but I am not able to figure it out. Sorry.

Overall Emigration to Indies to 1600 (Boyd, "Patterns of Spanish Emigration" HAHR 41 (1976) Andalucia - 34% Extremadura - 16% New Castile - 11% Old Castile - 18% Leon - 7.5% Basque Country - 4.6% Galicia - 1.6% Aragon - 1.6% Navarre - .5% Foreigners - 4% Unknown -

Origins of men of the Pizarro Expedition to Peru (Lockhart, Men of Cajamarca) Andalucia - 20.2% Extremadura - 21.4% New Castile - 8.9% Old Castile - 10.1% Leon -8.9% Basque Country - Galicia - Aragon - 1.2% Navarre - 1.2% Foreigners - 1.2% Unknown - 22%

Sample of origins of Cortes's men in 1519 (Thomas, Who's who of the Conquistadors) Andalucia - 148 men Extremadura - 69 men New Castile - 22 men Old Castile - 37 men Leon - 54 men Basque Country - 16 men Galicia - 12 men Aragon - 8 men Navarre - 2 men Foreigners - 18 men (Flanders, Italy, Greece, Portugal) Unknown -

From the two most famous conquest expeditions, you get a similar makeup as the overall patterns of migration. In some areas, there were greater populations of foreigners and that fluctuated at certain periods of time. For example, I work with German merchants/conquistadors in the Caribbean and northern South America. The majority of settlement patters for German-led expeditions mirrored those of Pizarro and Cortes. The only difference was a slight increase in foreign-born/identified settlers. There were a number of German-speaking settlers to Venezuela and Santo Domingo in the Caribbean who had occupations ranging from shipwright to choir director to miner. In fact, some 200 Central European miners came to the New World in the 1530s to look for gold and silver in the Spanish territories. Often we are limited to what we know about settlers. When traveling to Spanish-controlled territories in the New World, settlers were required to file documents and information with the Crown in Seville. This information was sometimes limited to a person's name on the official records. In other records, you might see a settler's name, their hometown, the name of their father or spouse, their occupation, or other details. The records are not always helpful.

For your other question, I recommend you checkout the podcast of Mestizo cultural and social history that u/DryLaw did here