A sensible five-day shape
One practical pattern is to start in Sri Vijaya Puram, move to Swaraj Dweep for two nights, then return to the city before departure. Whether Shaheed Dweep fits depends on confirmed ferry timings and how much pace you are comfortable with.
Use the 4 nights / 5 days package as a starting template, then adapt it to flight times and activity priorities.
Use the information first. Book the right service second.
Compare packages, request current hotel or ferry rates, or add water activities only after the route and dates make sense.