How can I make birthday cake flavored jello shots?

I have never made jello shots. I was thinking since unflavored gelatin requires 2 cups of liquid. I could do 1 cup of boiling water to dissolve the gelatin then here is where I’m not sure. Should I do:

1/2 cup cake vodka and 1/2 cup of white chocolate liqueur

or

1/3 cup cake vodka, 1/3 cup white chocolate liqueur, 1/3 cup cream soda

I wasn’t sure if 1 cup of alcohol would be too much, so I thought maybe the cream soda could balance it out. I am relatively new mixing (I’ve alway just got cocktails at restaurants), so if you guys have any other suggestions please let me know.

I am also planning on putting frosting on the rim of the cups with some sprinkles, and whipped cream on top for sure!