I need a name for both a boy and a girl. Also, it would be wonderful if they started with a J, C or K. It's kind of tradition...
Most Latin names in fact do not even contain the letter "K." The letter "C" is used instead. The letter "J" did not exist in Latin; the letter "I" was used instead (modern languages later differentiated "I" and "J"). Julius Caesar's name in Latin is GAIVS IVLIVS CÆSAR for example (note that Gaius is his given name). You can view ancient Roman and late Roman names for suggestions.
I think he/she is looking for a separate name for both genders, and not necessarily a proper name (i.e., more likely a noun or adjective).
Yes, (she, lol) is just looking for a C name for both a boy and girl. And if you have more than one for each, that would be wonderful.