That's quite a number of questions, but I'll try to answer them all as best as I can. First and foremost we need to know who these people were, and for that we go to Andalusia to the late stages of the n-th Castilian civil war, the one between Isabel and Juana. In that war, Juana's faction was supported by Portugal, as Juana was married to the King of Portugal. Our neighbours from the other side of the Miño had a remarkably strong navy, nearly on par with the Castilian one, and they could receive supplies from Guinea, mostly gold to finance the campaign.Given those circumstances, Alonso de Quintanilla, contador mayor de cuentas (literally chief accounting officer, but think of him as some sort of finance minister with powers of war minister) opted for a privateering approach: he would enlist the help of the sailors from the Atlantic coast of Andalusia, as far extending them an unofficial "patente de corso universal" (universal letter of marque) so these fellows would prey on every Portuguese ship coming from Guinea, and in that regard they were succesful. There are registered attacks by sailors from Palos (for the period 1475-1480) to Portuguese ships in the Canary Islands, the cape of Aguer, the cape Saint Vincent, and even as far as the Azores. They also occasionally preyed on English ships, and if need be on any ships, like Vicente Pinzón did in 1477 and along with his brother Martín in 1480. We are talking here of very seasoned veterans in the art of navigation, and the art of piracy as wel, not people prone to believe in any bullshit a foreigner would peddle.
When Columbus set up his banner for people to enlist in his expedition, he failed miserably. The people of Palos, Moguer, Huelva, Puerto de Santa María, did not trust this foreigner of whose experience they knew nothing. Columbus, though, managed to convince some of the natural leaders of the zone: the Pinzón brothers. Martín Alonso, Vicente Yáñez, and Francisco Martín were a trio of brothers from Palos, respected as merchants, rich men, and more than capable sailors: Martín was 50 years old and in good health, meaning his ships were safe and sound and his abilities were more than good, as by 50 he had not died at sea. Francisco Martín Pinzón was some 40 years old and a very experienced merchant and sailor too. Vicente was young, 30 years old, but the man was already a legend amongst his fellows: by age 15 he commanded his own vessel and had pillaged several places in Catalonia, including the port of Barcelona. But these three brothers took some convincing, in fact Martín was rather reluctant. However, after long explanations and consultations with friar Juan Pérez, a scholarly friar from La Rábida, and Antonio de Marchena, a consummate astronomer of the same monastery, Martín and his brothers were convinced that the expedition could be fruitful.
Besides the two friars, Columbus had talked in previous times with a captain from Palos, a certain Pedro Vázquez, who had been under the employ of the King of Portugal in the 1450s, and had reached the island of Flores, which is farther away than the Azores. This man was sure there should have been land farther away in the Ocean, and had spread these ideas in Palos, but to little avail. He had been a friend to the Pinzón brothers, to the Niño brothers, and particularly to Antonio de Marchena.
So, it was not Columbus who convinced the sailors to join his expedition. That job was done by the natural leaders of the region, not being it a simple task. This still begs the question as to how did these people convince some 120 men to join a most uncertain journey. The answer is not clear in any way, and the Columbian Lawsuits don't shed a lot of light on the matter, but there are reasonable explanations: Columbus, and the rest of his gang, had promised wealth. Christopher Columbus' idea was to go to the Indies, more precisely to isles of Spices. He had also promised, according to his knowledge from Marco Polo, Pierre d'Ailly, and Pius II, that there were massive deposits of gold, gems, silver, the whole lot. This was much uncertain, but the spices were a clear way of getting wealthy, and to establish a direct route to the Spice Islands would be profitable in and of itself. If the route was correct, it would have also been completely safe, as the seafarers would completely avoid the Portuguese ships that were along the coast of Africa, and in the Indian Ocean.
About the other question, I guess you mean to know if after making it back to Europe they went to America again. Of the 120 sailors that had sailed from Palos, some 30 died in America. In late 1492, Columbus set a fort, Fuerte Natividad, in the island of Santo Domingo, and left his brother-in-law Diego de Arana in command of it, along with 30 other Spaniards. They all died, most likely killed and eaten by the tainos. Of the people who made it back, some were fairly ordinary people, going back to their businesses in Palos, Moguer, etc. The officers are much better documented: Vicente Yáñez Pinzón went back to America more than once: in the last days of 1499 he departed from Palos, alongside other people, and in the early days of 1500 he discovered Brazil, and the Amazon river. In 1508 he went to America again, accompanied by Juan Díaz de Solís, navigating the Caribbean and discovering the coast of Mexico from the Northwest of Yucatán to 23º 30' N, which is around modern-day Tampico. Other people who went more than once to America having been in the first Columbian journey were Juan de la Cosa (owner of the Santa María), Diego de Lepe, Alonso de Ojeda, and other sailors.
Did any of the people that had joined the first journey become rich? Absolutely not. They were all shafted by Columbus, who had secured special privileges for himself, leaving the other people just about empty-handed.
Sources
Bache Gould, Alicia (1984), Nueva lista documentada de los tripulantes de Colón en 1492. Madrid: Real Academia de la Historia.
Campos Carrasco, editor (2014), Puerto histórico y castillo de Palos de la Frontera: protagonistas de la gesta colombina. Huelva: Universidad de Huelva.
Fernández de Oviedo, Gonzalo (1535), Historia General y Natural de las Indias. Seville: Cromberger. Modern edition by Juan Pérez de Tudela, 1959: Madrid, BAE.
León Guerrero, Montserrat (2001), El segundo viaje colombino. Valladolid: Universidad de Valladolid (doctoral dissertation).
Varela Marcos, Jesús (2001), Castilla descubrió el Brasil en 1500. Valladolid: Instituto de Estudios de Iberoamérica y Portugal.
VV. AA (1894), Colección de Documetos inéditos relativos al descubrimiento, conquista, y organización de las antiguas posesiones españolas de Ultramar. Segunda serie. Madrid: Sucesores de Rivadeneyra, vols. 7 and 8.