Best to apply now. The system still works but you may have to resubmit and try several times.

It is easier, although more expensive, to use a visa agent. I used ivisa.com recently which was quick and painless.

Given the Kenyans have still not updated Timatic, do not rely on the Notam as typically ground handling staff and reservations staff at your origin don't have access to the Notams and in this case the Notam refers to the FIR and all airports within it, rather than there being one for Jomo Kenyatta.