All your holdings are sitting in your demat account with CDSL. So it is as safe as it can get. Even if Zerodha Coin got hacked, it has no implications on your holdings. The only way to move your holdings from demat account is if you sign and send us the delivery instruction slip (similar to cheque leaf).
Yes you can have parallel portfolios. Once you start owning MF in demat, you don’t have to worry about folios and all.