It is
possible that some people have created Jalissa by deliberately blending
Alissa with a name that starts with "J". I know that occasionally people who create blended names try to interpret the "meaning" of the name as being blended from the original "meaning" of its component parts. But I personally don't think one can interpret the meaning of a created name this way unless you are absolutely sure that's what the particular parents intended. Most people who create such names are concerned with sound, not etymology.