The PCBs have arrived, more images below to illustrate the installation method.
HLE-105-02-G-DV-PE sockets soldered on top of M5Ms:
PCB lies in level with the mainboard:
Picture from top:
Picture from top, another set of HLE-105-02-G-DV-PEs (or HLE-105-02-G-DV-PE-LCs) and HDMI connector placed on PCB:
HDMI connector on the same level as mounting tab next to it:
Required cutout for CPS2 plastic case:
Case closed:
Rest of the components should arrive next week after which testing can begin. Unfortunately ADV7513 is no more available from trusted suppliers (technically it's on Mouser's and Digikey's inventory, but former requires you to be a HDMI licensee and latter has large minimum order quantity), so one needs to resort to other sources with that.