Once again, as hard as electrical issues are to diagnose....ALL of the info should be put in the first post because everything is critical. As much as you may have had relay issues in the past, they were not evident when this situation actually occured. You want to say your bike was running fine, battery went dry and you replaced it and now you have all of these electrical issues with lights not coming on and very little else for us to go on......Oh yeah, they came on once and everything was fine and then blacked out again.
Clarity in everything that happened up to the point of your original post (did you notice how you got off track with the tail lights not working and a particular relay to look at?) Those tail lights WERE NOT your issue, you may truly have a bad relay but read back to your original post and see that that wasn't the issue. A relay is a relay and causes alot of screwy issues.
All the relays don't have history
Back to question 1; does the bike start up and run when all this stuff is happening? Once again the question is confusing as to what the bike is doing....
Satan and redwing have come up with viable 'running' conditions where everything is good, now move on to step two.
BTW How could you have checked the CB but not bothered to turn the radio on to see if that was working?
I'm signing out of this post and not documenting anything because........it just has no value for future diagnosis stuff I save.
Don't mean to Dis you, I hope others keep posting and somehow help you solve this mystery