Is there something specific in the manual that gives 100% detail of what is reset in a system reset?
Usually no such detailed lists exist in manuals maybe because a 'Reset' resets everything (that has a default value).
For example in the manual, I see a list of default instruments, their panning, their volume, etc. Is there anything else?
Yes, there are many more.
1. All notes/sounds set to off.
2. Master volume, balance, tuning etc. are set to default.
3. All effects/effect parameters are set to default (e.g. Reverb presets such as Room, Hall etc.)
4. All Common Controllers are set to default values on all channels(Modulation, Volume, Pan, Expression, Sustain, Reverb, Chorus etc.)
5. All Pitch Bend ranges are set to default semitones on all channels.
6. All NRPN's are set to default on all channels.
7. All Banks/Instruments are set to default on all channels.
8. Other things I do not recall just now 😀
The more features a synth supports, the more are set to default by a reset.