I gather this tank is not being moved far? ie within the region.
If this is a move across town then there is no need to take several weeks to put the fish back.
I like to save at least half of the original water. This has nothing to do with any bacteria in the water (very little) but stability of pH etc.
If you use food safe containers you know they are good to fish, some plastics may not be. You can get big food/fish bins easily for a reasonable amount. I find chilly bins good. I have also transported a large number of cichlids from ChCh to Blenheim loose in a polystyrene box (they were in the box about 5 hours) with no plastic bags at all.
I have cycled a filter in Blenheim then taken it to ChCh and hooked it straight up to the new tank, added all the fish immediately, and all was good. Although some bacteria will die, as long as the filter media remains wet inside the canister (don't empty the water out of it), plenty will survive for several hours.
Empty the main tank, move it, fill it again with as much original water as you could reasonably manage, hook up the filter again, top up the tank, make sure the temperature is about right, turn the filter back on, put the fish back in. It will be the equivalent of a large water change.