Ah. They're great games. I'd recommend trying them if you have access to any nintendo consoles. Quite a few people miss the franchise unfortunately because it's a nintendo exclusive title. =/
Probably magic, like Malygos. Though, hopefully she won't follow his occupational decisions. xD
Plus, I think Cadence's rule over the Crystal Empire is merely a circumstantial thing. It was ruled under Sombra's tyranny likely long before she was born (considering she was around normal pony height when Twilight was filly-sized). So, I think it was just convenient for the princess without a kingdom to preside over the newly liberated Crystal Empire.