Not immediately. You can port the salary account, take the card, and use it extensively, hoping for an LE and card upgrade offer. Or decline the card and get it cancelled and apply again after 6 months.
Regalia generally requires over 1 lakh salary credit a month. And DCB requires 1.75 salary credit a month if you go via salary route. They do relax it at times, but that depends on HDFC.
Amex reward multiplier 1500*4 on the MRCC and 1000*6 on the Gold charge. That would be 1240 MR for MRCC and 1600 MR for Gold charge on spending 12K a month.
Amex cards don't give continuous renewal benefits on paying the fee as a feature but you can negotiate with them every year for some offer (eg, full waiver against some spend milestone, or additional reward points on paying the fee etc). But these are not always standard and we can't guarantee...
Plat travel + MRCC + Gold charge, this is the best combination. Plat charge can be considered if you get the reward points as joining bonus instead of the Taj vouchers.
They usually offer points against the full fee for Plat travel. That's most sought option. Plat reserve was useful to access the Amex lounges at Mumbai and Delhi but effective Sept 1 even that's going away.