For popcorn chicken, I find white breadcrumbs give the best texture, but you can sub for golden breadcrumbs, panko or crushed cornflakes.

Whenever you want to give your fries a little more TLC, I always recommend to soak them to remove excess starch. Tossing in baking powder or bicarbonate of soda helps them to crisp up a little as does cornflour if you add a tsp of that.
I've recently started to add it to my breaded chicken as well as it helps the crust puff ever so slightly which gives a lighter and crunchier bite. It also helps with browning!