I use Sol in my main team, and all those EX ability combinations I mentioned were ones I've actually used (or utilized the equivalent effect from a 2nd off-element kamihime).
Light benefits greatly from Amaterasu, who provides the type B debuff Light is missing and generally replaces Belobog. But that also begs the question: why go Light with Amaterasu and no Sol instead of Fire?
As for myself, I went with Water, despite landing the two best Light kamihime currently available (Raphael and Sol), because my team still lacked the necessary debuffs. Providing them would require running Mordred with Ambush for all content, and I prefer the flexibility of Water. I'd consider switching if I had Amaterasu though. The other perk of Water is that over the course of the next 6 weeks it gets access to 3 premium SSRs: Nike Unleashed, Cthulu, and Ryuuou. As such, Water teams have more room to grow, particularly with Miracle tickets. I looked ahead to the upcoming Light kamihime (available before the first Miracle ticket) and wasn't impressed. Light Tsukuyomi in combination with Diana compensates for Light's deficits, but she's not available until the second Miracle ticket (6 months away...)