Many of the components that came out with the logic board are held in place with screws and brackets.

Apparently, Apple is very concerned with making sure that all the connectors are firmly seated and won't rattle loose over time. Good on you, Apple.

Before we go any further: A mega thanks to Chipworks for sticking around into the wee hours of the night and helping us identify the packages on the logic board. Their handiwork (along with ours!) can be seen below.