1. Yes
2. No enquiry. They will show as separate cards on cibil.
3. No.
The only thing you should know is that you can use only upto the limit provided on each card.
And if limit gets increased on one card that are shared then it doesn’t mean they get separated. That only means you have one card with higher limit. And if you utilizse some amount on one card, then only remaining limit can be utilizsed on the other.