I also thought it might have been 'left' and 'right', but 'lion' and 'rabbit' make so much more sense and are much better lmao. It also reminds me of the white rabbit costume she wore for one of the W FACE tour videos, and her bunny outfit at the beginning of her 2005 first things tour (as well as the blue and pink mascot outfits), so rabbits make sense since they seem to be a theme she has used throughout her career.
I also really love 'imagine', it's one of her favorite ballads of mine! Maybe it's because I had broken up with my partner of 5 years shortly before 'Bon Voyage' was released, and 'imagine' really soothed me at the time. I just think the melody is really nice as well!
It's probably an unpopular opinion, but I actually think her ballads from recent years are some of her best. I find most of the Japanese fan favourite ones a little boring for me, to be honest, although I do like 'Moon Crying'. I tend to really like her album ballads or B-side ballads, although they also only ever get performed either once at the album tour or never, sadly.