Where is the likeliest place in Africa for homosexuality to be legalised? Intuition tells me that of those that are pink on your map, Senegal, Botswana, Namibia might be good candidates, but that is based on nothing very substantial
Mauritius, where homosexuality isn't actually illegal per se, but sodomy is would be number one. Apart from that the Seychelles where it is legal for women and they even have a couple of anti-discrimination laws (employment, ban on hate speech), but it is illegal for men - it has been proposed in their parliament.
On the mainland probably one of the other countries where the ban is a legal relict from colonial times. Of those, there are three where it is both legal for women and rarely enforced for men: Sierra Leone, Botswana, Namibia, but some prominent Sierra Leone politicians are against legalization.
Botswana and Namibia are very influenced by South Africa and Namibian gay couples can get married in SA and get it recognized in Namibia (despite homosexuality being illegal..). SWAPO is in total control and maybe they will at some point say its stupid to have it on the books. If the opposition ever wins in Botswana they would do it. They have a ban on employment discrimination of gays.
Senegal is Muslim and well-organized, so I don't see it happening there anytime soon. The only Muslim countries where it is legal are the ones where the state is too weak to regulate much anyway.