Well all the best for the 7 summits. Several questions, did you do Kokoda in the dry or wet, how many days did you take to do it, how fit and how old are you?
You will find Kili a walk in the park compared with Kokoda in terms of the walk especially going via the Shira Plateau route. Do Mt Meru first as a warm up.
It is the altitude on Kili and other mountains that will slow you down. if you have fitness, atitude and the mental ability you will be well placed on the other mountains.
BTW is you are going to Kili, fly Air Mauritius and go via Mauritius then onto Nairobi then Riverside Shuttle via Namangar border and onto Arusha or Moshi for your base. Air Mauritius has cheap flights from time to time to Nairobi and best to fly out of peak season and book well in advance.
Roger in Sydney