" Can i initiate her L2 EAD renewal as we have valid VISA and i94 number or does she needs to be physically in US for applying EAD renewal ?"
Her I-94 has no meaning once she has left United States. Another valid I-94 comes into picture when she legally enters back into US.
While she is outside United Status, she has NO STATUS. For L2 EAD, she MUST be on L2 Visa when she is filing petition.