Thankfully, found this post on hondatwins that mentioned the orange and light blue bike lines were actually active lines for when left or right turn signal was on – not that they were positive and negative general lines. It also mentioned a (cheap/simple, yay!) fix to use two 3-amp diodes and tie them in together. A quick putt-putt to Radioshack and $2 later…
I focus mainly on that in this image, but also some other related notes.
I also have my new speedo's neutral LED light now turning on when bike is on (but not running) – will see tomorrow if it also properly goes off when shift up when bike is running.