Want to Control Many Servos w/ Pixhawk

Very new to pixhawk and flight controllers in general here. I’m working on an aircraft with redundant control surfaces (inboard and outboard split elevons that crow brake) and therefore has many servo outputs I’d like to control with the pixhawk.

I wanted to achieve 16 channel capability by using one FrSky X8R receiver connected to the Pixhawk 4 via SBUS. Some of these controls could just pass through, but others I would like driven by the Pixhawk in certain flight modes.

What hardware do you use in addition to the Pixhawk 4 to make use of the 16 channels from the SBUS to drive something like 12 servos and 2 ESCs? When I look at the Quickstart guide for the PM07 power module, I see 8 "FMU-PWM-out"s (these see appropriate for servos, and require a separate low-voltage power connection) and then I see 8 "I/O PWM out"s, which appear to be high-current connections intended for controlling motors.

How would you set this up? Thanks for your wisdom everyone.