Well, I am of the opinion that all fluids change must be performed in time, be it CVTF, engine oil, coolant, etc. and if CVTF change is done timely, then there might not be any need of opening pan, etc.
Anyways, now, if the pan has been opened, we'll have to see what can be done now.
In this case, and as per my opinion (others can of course disagree), the CVTF Filter after cleaning or replacement (replacement must be preferred, instead of cleaning the filter via petrol, or any other fluid, etc.) must be put back.
Pan may be fixed back, after thorough cleaning of the magnets, pan, as well as that plastic tube, and applying silicone / gasket (whichever applies).
All bolts fixed and tightened in place, and now, the drain bolt may be opened, and CVTF may be started pouring in via CVTF Filler bolt.