Gabon to Namibia, border suggestions
 

I'm planning to cross in August from Cameroun to Namibia, by car (defender) and looking for some suggestions I could not recap from other posts.
1- Gabon to Congo: is there any new street going down from Mayumba to pointe noire? which would be the border town?
2- Congo to Angola: from Luozi, is it possible to go down directly to angola from Kimbamba-Damba? why everybodypasses from Matadi? is it nicer/safer or it is just for the visa? i'm coming with visa already on passport
3- Angola to Namibia: from namibe downward, is it possible to reach Namibia following the coast line? which boardcity would that be?

THANKS in advance for helping + if anybody around happy to share a beer over!!!

Ciao - Stefano