The duo joined the promotional play-off winners' pre-season training in Polokwane on Monday and have impressed the club's technical team.
According to a source at Leopards, an unnamed Ivorian is also being assessed by head coach Joel Masutha.
"Both Ayanda and Thabiso have made a great impression and if everything goes well they could sign," says the informant.
Gcaba, 32, ended a six-year stay with Pirates on loan at relegated Platinum Stars last season.
Fellow veteran Semenya, 35, was surprisingly released by City in June despite being one of the club's most consistent players over the past two years.
Lidoda Duvha earlier this week unveiled their new technical director Stefano Cusin and five player signings in the shape of Khethukthula Zwane, Lefa Hlongwane, Elton Kapinga, Themba Ndlovu and Chris Matombo.