Q1 - Every style file contains settings with rules for when to make that jump between octaves (in the section officially called CASM); it's a bit of a dark art to set these up when creating a new style. You could try going into style creator and changing the setup for the PAD channel on a style and see what happens.
Q2 - As far as I know, you can't change this on any Yamaha board. You can use 'fingered on bass' to control the bass note, but not the chord inversion itself. The exception is using the 'guitar' note rule, which generates chords that are apparently more natural sounding for guitar voices. Having said that, if you have the L voice activated, you can play any inversion you want with your left hand. The style parts will play the chord based on the root position, but the L voice will sound the notes you pressed on top of it. You can switch off the PAD part of the style if it becomes too muddy.