I'll look into tweaking the max for the Deep One Summon Siren.... I remember someone else mentioning that as well, so it was on my to-do-list.
As for juicing - looking at the code, it's meant to be non-lethal by nature unless you have the Bloodlust Trait. All damage is Stamina - based so unless your sex attack is super high, death should be unlikely. What kind of NPCs are you trying to avoid killing? Maybe if I see their stats I can figure out the issue.
Sadly, I don't have art for it yet.
That would require manually coloring the art and having it in a folder. It's not impossible, but impractical. Could probably be done with the right program. The PaletteChanger JSON files even give a list of all the images with 'skin' that would need to be edited if someone wants to try...
There is code (mostly commented out) for 'mind control' - I imagine it is/was meant for exactly this purpose... I can't imagine it's for Lona to be mind controlled, given the rest of the game.