Matej Koubek is on loan from Bohemians Prague to FC Vysocina Jihlava. He doesn't belong to Jihlava.
Proof: https://www.transfermarkt.com/matej-koubek/profil/spieler/635888
Radek Sirl is still active player , he plays in Zbuzany
Proof: https://www.transfermarkt.com/radek-sirl/profil/spieler/15663