Whisk the lemon juice, vinegar, avocado oil, mustard, garlic powder, ginger, salt, pepper, and paprika in a large bowl until emulsified.
Add the chicken pieces and sliced onions to the marinade, coating everything thoroughly.
Cover and refrigerate for at least 4 hours or overnight.
Remove the chicken from the marinade, reserving the onions and liquid.
Heat the canola oil in a Dutch oven over medium-high heat.
Brown the chicken for 6 minutes per side until golden. Transfer to a plate.
Add the marinated onions with their liquid to the pot. Reduce heat to medium-low.
Cook the onions for 20-25 minutes, stirring occasionally, until they caramelize and become jam-like.
Add the reserved marinade and chicken stock, scraping up the browned bits.
Return the chicken to the pot. Add the scotch bonnet peppers if using.
Bring to a boil, then reduce to a simmer. Cover and cook for 30-40 minutes until chicken reaches 165F.
Add water or stock if sauce becomes too thick.
Stir in the olives during the last 5 minutes if using.
Remove the peppers and bay leaves before serving.