You can’t get any more “powerful” than the strong, handsome and majestic [name_m]Alexander[/name_m] in my mind. I like [name_u]Jude[/name_u] [name_u]Spence[/name_u] too even though both are one-syllable. That name works because both of them sound different from each other. I would eliminate [name_m]Miles[/name_m] (with your S surname). Personally, I would not define [name_m]Ian[/name_m] and [name_m]Landon[/name_m] as “powerful”.