Hi,
I was to a Safari in Kenya this Christmas. With me I had my K20D with 16-50, 50-135 and A* 300 f4 (manual focus). My wife had the Q with standard zoom.
I found the A* 300 perfect as focal length for 90% of the wildlife shots because the animals are not too far and also for some landscape shots, as the landscape is so super broad. By the way I love the image quality of the A* 300, and the manual focus was not a big problem. Meanwhile my wife used the Q for the landscapes. That proved itself a good combination!
Other than that i used the 16-50 in the villages and only seldom the 50-135. So maybe as a standard you could keep the camera with best AF with the DA*300 and the other with 16-50, and switch the 300 with the 60-250 if you ever need it. I think you are well covered! (You can find my shots here in the "Kenya" section:
Gallerie - Tommaso Bientinesi - www.tommasobientinesi.it as a reference of what you get)
As for the rest: I did not use a tripod nor a monopod and I think it would have been worse. Those cars with detachable roof offer you a good support to lean on, and it is much better to be able to rotate or to change your position quickly. The driver will usually stop at your request and will probably be used to carrying photographers around.
I had 2 batteries with me but no grip, I just switched the battery when needed. I did not find a single place without electricity (and I was really in super-budget accommodations like campings or hotels for the locals).
Personally I prefer to shoot jpegs but that is your choice really. Every evening I deleted all the totally wrong pictures and most of the duplicates; that saved me space and also a lot of work at home. Nonetheless I ended up with over 3000 shots in 2 weeks, which would have been maybe 10000 without the deletion, so take enough cards!
Also, at sunset I changed my preset from 6500K to 8500K, I think it rendered the equator sunlight much better.
By the way, good luck for your trip and yes, having been there, I am VERY envious!
PS: remember the plug converter for electricity! In Kenya they have the 2-hole, "German"/Europe style plugs.