Kembo-Ekoko, a striker with UAE side Al Nasr, and Lorient midfielder Mulumba are in line for their first cap.
Both had previously rejected a number of call-ups to the national team.
Chancel Mbemba of Newcastle United and Crystal Palace winger Yannick Bolasie are also in the 26-man squad.
But there is no place for Dieumerci Mbokani, who is at loggerheads with Dynamo Kiev over his desire to quit the Ukrainian club after being heavily linked with a move to the English Premier League.
The Leopards will also be without their captain and Norwich midfielder Youssouf Mulumbu, who is recuperating after breaking a metatarsal bone in his foot early this month.
DR Congo will face a tricky game on 6 September in Bangui as CAR seek redemption following a 4-0 crushing defeat by Group B leaders Angola in their opening 2017 Nations qualifier in June.
Firmin Mubele Ndombe and Joel Kimuaki Mpela scored a goal each as DR Congo made their home advantage tell by beating a stubborn Madagascar side 2-1 on the opening day of qualifying round.
The two-time African Champions beat hosts Equatorial Guinea 4-2 on penalties to finish third at the 2015 Nations Cup.
DR Congo squad:
Goalkeepers: Joel Kiassumbua (FC Wohlen, Switzerland), Nicaise Kudimbana (Royal Antwerp, Belgium), Parfait Mandanda (Charleroi, Belgium)
Defenders: Issama Mpeko and Joel Kimwaki (TP Mazembe) Chris Mavinga (Troyes, France), Cédric Mongongu (Eskisehirspor, Turkey), Fabrice Nsakala (Anderlecht, Belgium), Gabriel Zakuani (Peterborough, England), Christopher Oualembo (Academica Coimbra, Portugal), Bobo Ugenda (Kabuscorp, Angola)
Midfielders: Chancel Mbemba (Newcastle United, England), Cedric Makiadi (Werder Bremen, Germany), Neeskens Kebano (Charleroi, Belgium), Jordan Nkololo (Caen, France), Remi Mulumba (Lorient, France), Paul-José Mpoku (Chievo Verona, Italy), Wilson Kamavuaka (Sturm Graz, Austria)
Forwards: Cédric Bakambu (Villarreal, Spain), Yannick Bolasie (Crystal Palace, England), Jeremy Bokila (Guangzhou, China), Junior Kabananga (FC Astana, Kazakhstan), Firmin Mubele (Al Ahli SC, Qatar) Jires Kembo-Ekoko (Al Nasr, UAE), Cedric Mabwati (Columbus Crew, USA), Jordan Botaka (Excelsior Rotterdam,Netherlands).
DR Congo have called up former France youth internationals Remi Mulumba and Jires Kembo-Ekoko for next month's 2017 Africa Cup of Nations qualifier against Central African Republic.