Yes, there would be a possibility of getting pregnant after having the implant removed, if there was sex without a condom the day before. That’s because the implant doesn’t always prevent ovulation. And, sperm can live for at least 2-3 days in a woman’s body, some say longer. So, if your partner had just ovulated, or did within a few days of the removal, and your sperm lived a few days, then yes, that could result in pregnancy once the implant was removed.
As far as return to fertility, it can be nearly immediate. If an implant is removed and pregnancy is not desired, the couple immediately needs to be using another method.