The Onkyo TX-NR7100 is the specific device I immediately saw was missing buttons. There is no specific mapping for this device, only the generic Onkyo profiles (A series, GXW Series, HTR Series Main Zone and HTR Series Zone 2, none of which really match my device). I use the HTR Series Main Zone mapping.
There is no mapping for "HDMI Out Main", "HDMI Out Sub", "Input StrmBox", "Input CBL/SAT", "Input Bluetooth", "Power On", "Power Off" (only has power toggle). I was hoping to use the Power On/Off instead of toggle because of how I am used to the Harmony remote (switching activities intelligently manages power status and keeps necessary devices powered on and powers off unnecessary ones) but now that I found out activity buttons apparently do nothing to trigger power on/off and just change the remote personality I imagine that's a non-starter anyway. The inputs and HDMI out settings are pretty essential for me though. I imagine there's more missing functionality but I'm not going to start testing things out until I at least get some minimum functionality and the missing buttons means it's stored for now.