GST Reversal on RCM

I think it same rule for all.

Yes if that input is used for providing non taxable supplies.

Yes As per Section 17(2) the credit is available in proportion to taxable supply . So ITC need to be reverse supply in proportion to Exempted Supply

But as per the explanation under 17(3) being inserted vide Amendment Act 31 of 2018, the Exempted supply not include the value of activities specified in schedule III , except para 5 of Schedule III.

Hence if you are supplying any goods or services which are cover under Schedule III except para 5 , the ITC reversal is not required.