Direct export of imported material from Custom warehouse

Yea. You can transfer. Your import charges will be purchases and export to Y country will be freight charges.

Yes, you can Export (it is not Transfer).You need to file Shipping Bill for export. Do ex-bond the Warehoused cargo and export.You need to file with Customs where the good is warehoused Invoice,Packing List, SDF  and other papers as the Customs authority may ask for.