Starlight fusing is a bit of a conundrum, because it's a quadruped fusing with a biped. Starkana would probably keep a bipedal form and the Beerus eyes, but her fur would be blue like Starlight's. Muzzle shape would be similar, but her hair and possible her tail would both be like Starlight's. She's probably have a horn and possibly wings as well. Maybe hooves for feet, like a satyr? Clothing ... eh, might be similar? Or maybe a bit more nature-themed.
Star2-D2 would probably look like an Equestria Girls human - blue skin, hair like Starlight's mane. Pony ears and possibly tail, but possibly not. Definitely more nature-themed clothing. Definitely a horn, possibly wings. Definitely hands and feet.
Also, maybe Starlight/Ryu? They could be either bipedal or quadrupedal, and definitely a kirin.
Though in all cases, it depends on who's the primary influence and who's the secondary influence. After all, if we have Starkana, there's also the possibility of Vodlight. If we have Rylight, we could also have ... Staryu? Heh. XD
Well, most of our characters either are or will be immortal, and we do have access to time travel magic (in theory).