Falb fee is pharaoh (two wild type genes) plus fee (homozygous or heterozygous?)
An Italian is a fawn and pharaoh (Manchurian would be two fawn genes, no wild).
It would be a simple punnet square for each gene set as they inherit separately. You’d get half Italians and half pharaohs, for the base pattern.
Assuming a homozygous fee gene all offspring would be heterozygous fee (so falb fee or pearl), if heterozygous you’d get half heterozygous fee and half wild type (so 25 percent each wild, Italian, pearl, and falb fee.
If you want more white on your pearls, aim for homozygous fee (two copies will wash out more of the base color so breed your fee carriers to homozygous fee birds) also make sure you don’t have one of the pattern enhancers in your mix which gives you more barring and streaks (sparkly, pansy, calico, also separate genes!).