I see what you mean, and i never gave it any thought as i dont have 10 input sources. There are nine selectable named inputs (Devices). Bluetooth and Tuner are non-assignable. so that leaves 7, which is what you need right Beachbum? Cable/sat, Disc, Game, Media, Server, Aux and TV. Sucks that we cannot rename these !
Incidentally, I used the front HDMI for a Roku stick a few weeks ago, and once plugged in, i believe the 976 defaulted to it without me selecting it in any way, but im not totally sure about that as my memory is not what it was. If this is true, then it is not assignable and it will override.
There is an audio selection called "Direct" and unless im missing it, i dont see it explained anywhere in the manual other than page 46 where you can list your connections. I have 7.1 analog cables connected from my Oppo and "direct" allows their use. I wonder if your analog sources can also use this mode, but i dont think so. No DSP or bass management is applied to this. I have a turntable that is using an analog input, but i have not tried it on "direct" as i assigned it to aux and Dolby pro IIX music. I should try "direct" and see if it works.

But the more i think about it, i think you are out of luck if you have more than 7 input sources !