Timlin came through the ranks at Craven Cottage, where the 20-year-old started as a left winger before switching to central midfield.
He has made two first team appearances for the Cottagers, in the FA Cup and Carling Cup.
Ehui is a pacey 19-year-old striker, he is originally from France and can use either foot.
Timlin has been handed shirt no.31, while Ehui will wear no.26.