Jovante is a blend of
Jovan with names like DeVante or
Dante. There really isn't any etymological meaning to the -te on Jovante unless your parents deliberately thought of one. Otherwise the etymology of Jovante is simply "modern blended creation."
I suppose that Letaurean means "the Taurean" since that's what you yourself created it to mean. But you can't just put a French article in front of a non-French word and say that it means "the Taurus" in French. You would have to consult someone who knows French to find out if "Taurean" is used in that language for someone born under the astrological sign of Taurus.
Lemar is another spelling of Lamar. Lamar is a surname which goes back to French and originally meant "the pond", referring to an ancestor who lived by a pond.
Just out of curiosity, how old are you and how did your aunt come to give you the task of naming your newborn cousin? It's highly unusual for a cousin to get that sort of honor. Was it simply because he was born on your birthday?