Full charge actually refers to using the sheath to defend against attacks. It eventually charges up and can be used to deal a blow far stronger than normal, depending on what was blocked.
At the current level, it only blocks kinetic energy. And it is a single blow.
Sonics-Edge is applied to weapons usually to boost their damage. It creates a cutting edge of sound, vibrating its target into parting. It could also be applied to your hands, if you wanted to cut something.
Sonics-Bow creates a string that can impart kinetic energy onto the arrow. Just draw it back to aim, and release.
It is assuming it's a quick action in combat. Sonics-Bullet Blast is using the sheath in it's Bullit Form to send a blastwave of compressed sound.
This of course means it can be used in this form to propel Kana Blanc around. Actually firing it is going o knock her off her feet otherwise.
Bow form is the only one that needs Sonics to function. The other blade forms all have an edge already, not counting Sonics-Edge.
Creating new skills with my Psyche requires research obviously. As does refining them.
Plus they would likely work by giving me a new combat slot or 2 each level. I can only have so many active at a time on me after all.
Mastering any of the basic Sonics should also grant me a free slot, since I know that program inside and out by then.
Angel Player uses sound to start with. But mastering Aetheric Courses could give me new options to program in.
Sound to Kinectic- is the primary option basically. But Sound to Fire AND/NOT Kinetic is like the above mentioned.