Lidakevicius joined Barnsley's Academy in August 2011 before turning professional ahead of last season.
But the Lithuania U21 international failed to make a first-team appearance for the Tykes.
Portuguese winger Silva moved to Oakwell from Liverpool last summer but failed to make an impression.
The 19-year-old leaves Barnsley after making only one first-team appearance.
Meanwhile, Christian Dibble has moved to Oakwell from Bury after speaking to Barnsley goalkeeper coach Ian Willcock.
"I'm obviously very pleased," Dibble said. "I was very surprised because one minute I'm signing for Bury and then suddenly I got a call off Willco saying they wanted to sign me so I'm very pleased about it."