As can be seen in the adjunct Timeline, there were many "events" in Spanish history that played some part (minor or major) in the establishment of Carolina. The year that Christopher Columbus discovered the New World (1492) was when the country of Spain began its national existence - after merging the separate kingdoms of King Ferdinand (Aragon) and Queen Isabella (Castille). This new union was soon at war with others who did not want to see it continue, and after that, many more wars would arrive on the shores of Spain.
Of all countries in Europe, none were in better position to dominate all of North America than Spain.
On May 4, 1493, Pope Alexander VI (who just so happened to be Spanish) issued his Papal Bull entitled, "Inter Caetera," officially declaring a Spanish-Portuguese "agreement" on "who gets what" of the New World. This "agreement" stated that a north-south meridian would be established 100 leagues west of the Cape Verde Islands. Soon thereafter, the Portuguese appealed, and to make a long story short, the Treaty of Tordesillas on June 7, 1494 changed this north-south meridian to 370 leagues west of the Cape Verde Islands. This is roughly at what is today known as 46° - 37' W latitude. This agreement with Portugal guaranteed that Spain would "own" all new-found lands west of 46° - 37' W latitude, whereas Portugal "owned" all lands east of that line. Ergo, Brazilians speak Portuguese and the rest of South America speaks Spanish.
The Spanish came to the New World looking for gold, not to colonize, per se. They did establish a base of operations on Hispaniola and even appointed governors, complete with staff and all the trappings. The governors and their staffs focused on sending out expeditions to find gold, and they did just that. Not all expeditions were fruitful, but they had to be made in order to determine if the previously unexplored lands had any of the precious metal.
Herdando de Soto first explored the interior of Carolana in 1540, but found no sizeable quantities of gold anywhere - so, he went on into Tennessee and then headed south to Mobile Bay. Carolana was interesting, with mostly friendly natives, but - no gold. So, the Spanish made no great efforts to settle until 25 years later. Lucas Vasquez de Allyon did implant a small group on Winyah Bay, near present-day Georgetown, South Carolina in 1526, but he died while there and his troupe packed up and headed back to Hispaniola.
In 1566, Pedro Mendenez de Aviles brought a larger group to Port Royal Island and the Spanish had a foot-hold in Carolana for two decades. But, their focus was on Florida, the Carribean, and South America. When Sir Francis Drake attacked and destroyed St. Augustine in 1585, an "undeclared" war between England and Spain followed for another sixteen years - both sides sniping at each other's New World settlements in the Americas, as well as the Spanish colonies in the Pacific.
Whereas in this "undeclared" war, England definitely scored more points - especially by defeating the Spanish Armada in 1588 - this war was "child's play" compared to the other wars Spain was drawn into over the next two centuries. Additionally, North America was not that important to Spain, thanks to "more pressing" problems.
Spain had its eyes on The Netherlands for decades when it finally decided to invade in 1568. Having The Netherlands would give Spain a strategic location from which to base any future operations against its two major rivals - England and France - which had been a thorn in Spain's side for a long time. Spanish royalty scored many "big points" when it joined the Hapsburg lineage in marriage, and subsequently Spanish rulers now ruled the entire Holy Roman Empire at the time.
Of course, this "ticked off" the rest of Europe, and everyone was soon posturing to take Spain down a notch or two. When Spain invaded The Netherlands, the other "power - wannabes" decided it was time to take down the Spanish. England did not participate immediately, but did eventually. The Eighty Years war (1568-1648) pitted Spain against various alliances - on and off - for just that - eighty years. In 1648, Spain finally called it quits and The Netherlands became a truly independent state.
It wasn't long before Spain was back in action - first with the French (1635-1659), then with Portugal (1640-1668), then again with the Dutch (1672-1678), and on and on, as shown in the "timeline."
The Protestant Reformation did not play a big role within the boundaries of Spain, which remained very Catholic. To make up for it, the Spanish created the Inquisition - and this was one of their biggest internal focuses for years and years.
But, Spain did play on the European stage because of the Protestant Reformation. Religious wars sprang up all over Europe and of course Spain was dragged into many of these to side with the Catholics against the Protestants. Another drain to all the gold Spain took from the New World.
Therefore, Spain never expended much real time or energy on the eastern seabord of North America after 1585, giving the other "world powers" free reign to fight over it amongst the remaining three interested parties - England, France, and The Netherlands. We know how it ended up.
Between 1585 and 1701, the Spanish in Florida did like to "stir up problems" for the English, so the Spanish used the local native Indians as their surrogates to raid English settlements in Carolina. In 1701, the War of Spanish Succession (also soon called Queen Anne's War) broke out in Europe, and in the colonies, there were minor skirmishes between the Spanish and the Carolina colonists. The colonists responded by attacking the Spanish province of Apalachee in northwestern Florida.
At the conclusion of this war, the Spanish instigated the Yamassee War in Carolina - it lasted two years. After that, the Spanish pretty much left Carolina alone.
With Spain's focus elsewhere, it is easy to accept that the Spanish "influence" on Carolina was minimal. Their biggest "contribution" to Carolina was their explorations and the resulting maps that were soon available to everyone in Europe. Since the Spanish had explored so much more of the New World than any other European "power," it stands to reason that most "place names" in the Western Hemisphere are of Spanish origins (that is, except for local/native names - they were even used by the Spanish).
Because the Spanish maps of North America were the first published in Europe - many in the early 1500s, some of the Spanish-named locations along the eastern seabord (north of Florida, of course, where many Spanish place-names are still in use) are still being used today. Not many, but a few. The biggest "impact" as a result was the long-lived confusion among the Carolina settlers who came from the British Isles, France, The Netherlands, German, Switzerland, etc. - but, somehow everyone learned to live with almost every river having two names - they just knew what the other person meant.
For example, the Spanish had named the Cape Fear River as the Rio Jordan. It was named this because they had discovered it on the "feast day" of John the Baptist. The name stuck for many decades because it was named thus on so many Spanish maps of the 1500s and 1600s, and the Spanish kept calling it Rio Jordon on maps well into the 1700s - even though the English had first named it the Clarendon River in 1665, then changed its name to Cape Fear two years later. But, when Carolina was well settled, all the locals knew that if you said the Jordan River you meant the Cape Fear River.
The Spanish named Cape Romain as Capo Romano in the early 1500s - and the English tried for years to rename it, but finally just gave up and used the anglicized version of Capo Romano from then on. It is still called Cape Romain today.
Finally, the next most important "influence" that the Spanish had on Carolina was their "money." Spanish "pieces of eight" were everywhere along the eastern seabord, and since they were made of silver, every place in every colony readily accepted them as "legal tender" for anything purchased. This continued even well after the new nation of the United States was established - Spanish "pieces of eight" were legal tender until 1857, when Congress finally abolished their use.