Considering the existing colors for your character (the jacket in HEX 488BD1, hair in D76739, accents in E0C849, and a backpack in AB3044), a great choice for the pants could be a deep charcoal or dark navy to provide a strong contrast while still integrating well with the overall palette.

Suggested Colors:

1. Pants Color: Charcoal Grey - HEX 4B4B4B - This deep grey will contrast nicely with the brighter colors of the jacket and hair while remaining neutral and sophisticated.

2. Accent Color for Pants: Muted Burgundy - HEX 8B3A3A - This color will provide a warm, rich accent that ties in with the red of the backpack (AB3044) without overwhelming the palette.

Here’s the updated color palette in JSON format:

json
{
  "palette_name": "Character Color Palette with Pants",
  "colors": [
    {
      "name": "Jacket Blue",
      "hex_code": "
          
          #488BD1
       "
    },
    {
      "name": "Hair Orange",
      "hex_code": "
          
          #D76739
       "
    },
    {
      "name": "Accents Yellow",
      "hex_code": "
          
          #E0C849
       "
    },
    {
      "name": "Backpack Red",
      "hex_code": "
          
          #AB3044
       "
    },
    {
      "name": "Pants Charcoal Grey",
      "hex_code": "
          
          #4B4B4B
       "
    },
    {
      "name": "Pants Accent Burgundy",
      "hex_code": "
          
          #8B3A3A
       "
    }
  ]
}

This palette introduces a strong contrast with the charcoal grey pants while the muted burgundy accent ties back to the red of the backpack, creating a cohesive yet visually interesting character design. Would you like to explore more options or variations?