The brooder set up looks good. You have a nice roomy coop, but it's always hard to make sure all the pieces fit together right. It's good that the chicks are in immediate sight of the rest of the flock. That will make the next integration all the easier.
I like outdoor brooding and I've been putting chicks outside from day 1 for a few years now. Fingers crossed, I haven't had any issues.
I converted an old rabbit hutch into the brooder -- insulated on the top and three sides and placed it in a sheltered area in the chicken run. I use a...