the simple answer to the question is: no, they don't have actual meaning, just symbols of adjectives.
if u wanna know further, well, the origin of Japanese is actually greatly affected by the chinese wu dialect, in Wu, we use 兮（the same pronunciation as し） to express emotions and determine the degree of the adjectives. as time goes by, some しs are gradually turned into いs.
u can google some papers by using the key words like "japanese origin" "Wu dialect" or something.
goodluck & have fun!