Non PINS Demat Account query for Non US based NRI

Hey all, I am a new member here,
had a few Qs regarding NRI trading and Demat accounts.

suppose current setup is :
1- Resident demat and trading account linked to NRO bank account – is this combination valid and OK to continue ? if intention is to buy, sell , hold on non repatriable basis.

2-if not, can resident demat be converted to NRO demat or a new NRO demat is to be opened and holdings transferred ?

3-any one has experience with kotak securities or sharekhan to convert demats and trading account. any tips on the same.

4-when we say NRO NON PIS/PINS – this PIS or PINS is an account opened by a BANK right not by the trading firm ?

5-what happens to the dividend if thats supposed to be coming to bank account while demat is being converted to NRO.

thanks so much !
tc.