I've reviewed them more and found a few more differences. Scar has his dew claws ripping in on Mufasa's paws, but not Simba's. Simba's paws are still on top of the ledge holding on as Scar grips him, meaning his weight isn't pulling Scar's claws in deeper like poor Mufasa (who is also more muscular and heavier than Simba). Mufasa, though, is on the side of that cliff climbing up, and his paws are below the ledge Scar is on. Simba merely manage to find a foothold on Pride Rock he could use as leverage about the moment rage compelled him to go after Scar. Mufasa was on a sheer cliff and barely scrabbling to hold on, thus having no leverage for a leap if could manage it.
and I've played with tons of fire effects to know about the lighting it gives off....also noticed it from real flames too lol.