Based solely on the images, I would tend to not think your belly button is infected. Obviously, this assessment is best made by an in person exam by your operating surgeon. Sometimes a patient can have mild separation of the skin edges in a belly button and the body will need to fill those areas in. These is initially done with kind of a protein "goop" that can resemble pus but is not really a sign of an infection. If the area was infected, I would expect to see more redness and tenderness in the surrounding skin, rather than just the protein discharge between the edges that are trying to heal. If you were my patient and I came to the same conclusion after an exam, I would encourage you to wash the belly button with soap and water daily and moisturize it with a bland moisturizer like Vaseline or Aquaphor until it heals in. Regarding the lower firmness, that is much harder to draw any conclusions from based on your picture. Sometimes, patients can have firm spots near the incision from the dissolveable sutures, as well as fluid collections and infections. Other times, some of the fat may inside may get stressed too much and those cells can die, creating a firm spot of scar tissue known as fat necrosis. I would encourage close follow-up and re-evaluation of this area by your surgeon if it continues to concern you.