Among them are two goalkeepers, Congolese Will-Cesaire Matimbou from Paris Saint-Germain and Ivorian Nicolas Tie from Chelsea.
Defender Hamza Mendyl from Schalke 04 is one of several Moroccans based abroad selected for the home-and-away second-round eliminators.
Congo Brazzaville, the Ivory Coast and Morocco are among the countries seeking overall victories and places in the third qualifying round during June.
The seven third-round winners join hosts Egypt in a November tournament where three places at the Tokyo Olympics will be up for grabs.
Olympics qualifiers are restricted to under-23 footballers with three over-age ‘wildcards’ permitted at the finals.
Getting the likes of Matimbou, Tie and Mendyl with home-based talent is one challenge facing Olympic coaches.
Another is compensating for the lack of preparatory time, with South Africa coach David Notoane probably speaking for all his counterparts when he lamented the short build-up.
“I would have loved more time to prepare because I share with all other Olympic football coaches in Africa the challenge of building a team from scratch.
“The harsh reality is that we have very limited time to work on the training field so it is essential to hit the ground running,” he told reporters.
Notoane had hoped to include Crystal Palace defender Nikola Tavares, born in Cape Town to Croatian parents.
“He is a left-footed centre-back, a rarity in our country at the moment, but his South African passport is out of date so I had to omit him from the squad.”
South Africa face a tricky start away to Angola in Luanda Friday with the return match set for Johannesburg four days later.
Morocco tackle the Democratic Republic of Congo, a strong football nation at senior level but one that continually fails to make an impact in age-limit competitions.
Congo Brazzaville are up against Burundi, who snatched a second-round place on away goals thanks to Cedric Mavugo netting with one minute left in Tanzania.
The Ivory Coast squad that will take on Niger includes Peru-based midfielder Edgar Dakoi and striker Loba Arnaud Ake, who plays his club football in Mexico.
Nigeria, who won the 1996 Atlanta Olympics tournament, meet Libya with the first encounter in Tunisia for security reasons.
Cameroon are the other African country who have been Olympic champions, edging Spain on penalties with the help of Samuel Eto’o in the 2000 Sydney Games title decider.
The central Africans have a bye to the third round as opponents Sierra Leone were disqualified owing to a FIFA ban imposed last year over government interference.
An Owusu Kwabena hat-trick helped Ghana crush Togo in the first round and they confront Gabon next with Accra hosting the first leg.