I read your problem start to finish of what you described. I believe i know what the problem is, and what i will do is explain some I hope basic mechanical mumble jumble to explain what I believe is wrong and happening.
You were driving along and and all of a sudden it stalled and then your tried to start it and, second attempt you heard click in right side cover area. that was your starter relay that was trying to work. Now I realize that you just replaced your starter relay, which is ok, but that was not you have checked your battery you say, and checked all battery wires, and you say that is ok. Here is where the problem is, this problem is a short in your ignition, or worn contacts in your ignition. Point is it is your ignition, ASSUMING that all wires from ignition via to the battery are hooked up good and strong, no loose connections, no corroboration and battery was tested good.
See here is the deal, no matter what could be wrong with the bike starting or not, or starter, or relay or inline fuse etc, would have nothing to do with the fact the headlights and gauges are not working, which MEANS simply this. If your head lights and gauges are not coming on when turning the key on, this means there is a short in the ignition (where key engages) Let me explain more.
When putting in the key, sometimes the contacts get warn, mostly cause from age, and ware and tare.In side the ignition are several wires that operate your fuel pump/relay and solenoid, head lights,tail lights, dash gauges, and so much more. Main thing it also does and nothing will work is it is connected to your charging and electrical system, which means to your battery. Because none of your lights are working, this tells me there is ONLY two things this can be, now we can eliminate the battery itself and connections based on you saying you checked this, so this leave ONLY ONE area, and that is the ignition. This could be a short,loose wire that brings the hot power from your battery, inside ignition where key has worn contact to trigger the hot control to the battery, Bottom line is, if you turn key on and can not get any power or headlights etc, then ignition needs to be replaced or wires directly to it checked for frayed or loose connection. The tumblers in the ignition, is nothing to really see, could be just worn, and replacing whole ignition is best. You can also test ignition by using a 12 volt wire tester, to see if you have hot lead lighting up that goes to battery, when key is turned on, and if not for sure it is whole ignition needs replacing. I hope this helped you with out getting to lengthy on explaining whats happening. But that is the area where the problem for sure is. Thanks Mike , from fixya.