Both players have put pen to paper with The Chilli Boys, arriving as free agents and are thus eligible to be registered immediately.
Timm, though, is still awaiting his international clearance certificate from the United States after previously turning out for Phoenix Rising in the USL.
The 26-year-old playmaker is a product of the Matsatsantsa youth academy, which he left in 2011 to join Bidvest Wits.
After two-and-a-half years with the Clever Boys, he joined Mpumalanga Black Aces after an initial six-month loan spell, before then moving over to America upon Cape Town City's takeover of the club.
He has since returned to South Africa, and has been training with Eric Tinkler side's for the last couple of weeks, managing to earn himself a one-year deal with a one-year option.
Meanwhile, Mokeke, who also graduated from the SuperSport academy before joining Ajax Cape Town in 2010, was released by the Tshwane club at the end of last season and will be looking to get things back on track after a brief hiatus.