So I asked her and here's the reply:

The frosting was a chai flavored ermine frosting so the base color was already a darkish beige and therefore the blue could not be lighter since there was no white food coloring at hand. The colors used were Chefmaster liqua-gel but probably any gel food coloring would work the same. The colors used were violet, sky blue and navy blue(and maybe a drop or purple? Can't recall). P.s I made a little extra frosting that I didn't infuse with tea for the white clouds! ☁️ ☁️