I want to use the four letter pHat together with a Blinkt! strip. I wonder if this is possible. In a different posting I read the Blinkt! uses max 480mA, will this influence the pHat?
480mA is a comfortable over-estimate, assuming 20mA * 3 elements * 8 LEDs. You'll no doubt find it'll run fine alongside Four Letter pHAT.