First Time Brewing, I accidentally ordered all my grains in the same bag.

I'd just brew it as you have it. Only increase your mash time to help in converting the high percentage of flaked products.
I'd go at least 90 minutes and up to 2 hours.
It'll make beer and it'll be fine.
Flaked barley yeah maybe
But I wouldn't put roasted barley into a witbier.
I would probably use unmalted wheat, or flaked wheat, pilsner (or pale ale) malt, coriander and (bitter) orange peel.
Maybe flaked oat.
But it is your beer! And it will be beer!
As said before, it will make beer.
lol thanks, I’ll give an update once I start, if anyone cares.
We care!
There is a wealth of brewing knowledge on this forum, not to mention that we have a good community here.
Even the most experienced of us are learning more about the craft every day, many times from contributions to posts like yours from a beginning brewer!

I found this on toasted flaked barley.
I have only ever used flaked what, and flaked oats.
Interested to hear what you end up doing with this, and how it turns out!