If certain goods/ services are used partly for business and partly for non-business purposes, will the credits be allowed in full or proportionately?

The credit on goods/ services used partly for business and partly for non-business purposes will be allowed proportionately to the extent it is attributable for business purposes. The manner of calculation of such credit is provided in Rule 42(1) of the CGST Rules, 2017.

(ICAI FAQ PUBLICATION 06-09-2017 -: Apportionment of credit and blocked credits: FAQ NO.11)

Whether all assesses/dealers who are already registered under existing central excise/service tax/ vat laws will have to obtain fresh registration

No. Every person registered under an earlier law and having a Permanent Account Number issued under the Income Tax Act, 1961 shall be granted registration on a provisional basis and a certificate of registration incorporating the Goods and Services Tax Identification Number (GSTIN) therein, shall be made available on the Common Portal. Further, the proper officer will issue a final registration certificate after calling for information and documents.

(ICAI FAQ PUBLICATIONS 06-09-2017 REGISTRATION: FAQ NO. 34)