More importantly the Lithium Ion batteries can replace lead batteries in existing subs without a lot of bother.
The Akula upgrades will likely centre on replacing electronics... think how far computer technology has developed since the 1980s in terms of processing power and power consumption etc etc.
They will likely install Sigma battle management and communications system and probably also launchers for Kalibr (also known as Club or Klub) that will be compatible with Oniks/Brahmos/Yakhont.
Regarding the Kuznetsov it was not scheduled to go for refit till 2013 anyway.
Minor correction... the 677 is not going to be serial produced, its faults will be corrected and the design improved and it will be produced as 677M.
Also it makes sense to focus on the upgrade of one Kirov class vessel for now. The addition of Oniks to replace Granit is necessary as Granit is out of production.
I rather suspect they will install the Sigma BMS and communications system as that is being installed on all RuNavy vessels from corvette to carrier.
Other than that they might upgrade the sensors and weapons that are ready for deployment which may or may not include Redut, and Pantsir-S1. New large AESAs might not be ready yet, but for now I think this will be a relatively cheap straight forward upgrade, and in 5-10 years time they might get a much more substantial upgrade including propulsion... they will be developing new compact and powerful nuclear reactors for their new carriers and one would certainly suit the Kuznetsov to replace its complex combined propulsion system.
Later upgrades might even include the 152mm gun based on the Coalition artillery system with guided shells able to hit targets up to 80km away.