This is difficult without more information, especially a list of names of other developments in the area so as not to duplicate. I can understand your client not wanting to share this information on a public forum but it's too much to ask without the necessary info. Also, as Grahame and Marlie have pointed out, it is the sort of task that people get paid good money to do...
The usual thing would be to use a Spanish/tropical/Dominican sounding word that is familiar to the ears of the target market and that evokes nature, relaxation and natural beauty (some more serious than others) - Las Magnolias, Las Amapolas, Palma Real, Brisas del Mar, Mondongo Mansions, Amber Cove, Bachata Bay, Puerto Escondido, Valparaiso Villa, Punta del Norte - or some faraway exotic/jetset location - Colinas de Beverly, Montecarlo Bay, Capri Cove, Villa Cana, Marina Azul, Bali Hai Bay... maybe whimsical/mystical - Seventh Heaven, Merlin's Retreat, Shangri La, Nirvana, etc. I'll stop now because the last few sound like names of beach cottages in Herne Bay...