Kipyegon finished second in Doha.
Duplantis said he was "just trying to get a feel for outdoors" at the event, held at Hayward Field.
Kipyegon will be out to fine-tune her preparations for the World Championships when she lines up for the Prefontaine Classic.
The posts on Facebook have since been pulled down.
Tuwei has urged athletes who are living in fear to report to the federation.
Omanyala boasts of a world-leading time 9.85 seconds over the distance.
Cheromei, in his statement, said that many parody accounts were created by the fraudsters.
The athlete was feted at Riadha House in Nairobi Wednesday morning after flying in from Eldoret.
Yego, 33, leads the team.
A majority of elite athletes are battling a range of emotional and physical abuse.