Ake and Koulibaly are officially at Stamford Bridge now and it looks like the rumors about Kimpembe and Kounde will end with these two defenders.
Yes, Chelsea doesn't need more center-backs now since they already signed Ake and Koulibaly. They should end the negotiation to sign both Kimpembe and Kounde. These center-backs are expensive, Chelsea mustn't want to waste money because they are not urgent to buy more center-backs. I believe Chelsea management focuses on looking for a new CF. They need at least 1 top CF after Lukaku left the club. Lately, there is a rumor that they are trying to sign CR7 or Lewandowski.
I think Chelsea does have a lot of defense and unfortunately at this time there is no signal to add attacking players or midfielders because they think if you add too many players it will make the salaries paid for the players swell, I heard rumors that a club as big as chelase does not provide priority for these two professional strikers so I believe there is no guarantee either of them will go to Chelsea.