I don't think anyone has answered that bit yet. No, that's not possible. The exact same inventory is used for award and upgrades, so in effect, if there is no award seat available, then it would not be possible to use avios to upgrade ether.

You mention year end - that's peak season for Kenya so I would not hold my breath. Also, in recent months, award seats in CW and F have arguably been a lot harder to find than before (and they were already not easy to get in the first place).