Good sub, but Mega Evolutions can't change HP, so you'll need to put those 10 points elsewhere. Also, you're only allowed to give a new Mega up to 2 new moves, so just remove 2 moves from Amph and 1 from Audino.
Name of Pokemon: Ampharos
Name of New Mega Stone [X or Y]: Ampharosite X
New Mega's Type: Electric/Fire
New Mega's Ability: Elemental Body*
New Mega's Stats: 100/125/105/105/105/70