I have been to all three of the resorts that you mentioned and in the briefest of terms, Mauritius (while a great place) is a very large resort much favored by families on package tours and would not be my choice for a Honeymoon.

Forgetting your travel preference for the moment, I think that both the Seychelles and the Maldives would be excellent choices for a Honeymoon. The Hilton Seychelles is small, intimate and luxurious; the Conrad Maldives is a medium size resort (150 villas spread over two small islands) also with luxurious appointments and a high level of personal service. However, do NOT base your choice on the assumption that you will get an upgrade to an over water villa as this would be a triple upgrade. It would be worth the cost of a paid upgrade for your honeymoon.

I suggest that you plan your air travel using some dummy dates and check the available routings, departure and arrival times and having regard for check-in times. At the Maldives, if you do not arrive during daylight, then you will have to arrive the previous day as the air taxi to the resort only operated during daylight hours.

I will be very surprised if you can obtain good connections to MLE using a first class award ticket.

Good luck