Deemed export billing at 0.1%

As per notification 40/2017

yes a register supplier can bill to merchant exporter @ 0.1℅
under following;

The registered supplier shall supply the goods to the registered recipient on a tax invoice;
Goods to be exported within a period of ninety days from the date of issue of a tax invoice issued by the registered supplier.
Merchant exporter shall indicate the GSTIN and the tax invoice number issued by the registered supplier in the shipping bill or bill of export, as the case may be;
Merchant exporter shall place an order on registered supplier for procuring goods at concessional rate and a copy of the same shall also be provided to the jurisdictional tax officer of the registered supplier;

query 3:
in eway bill GST tax is optional & moreover u dont need ito put tax rate , instead u can put GST TAX Amount

Show such bill in B2B sale

For more clarification plz go through the above Notification

Sir,

As goods are delivered directly to port in Maharashtra from Hyderabad,shall we charge CGST and SGST or IGST.In this case both the supplier and recipient are registered in Telangana.