Will there still be a need for LF for day 2+, or will suppression of IADS on day 1 mean its unlikely LF will be required?
Regardless of the effectiveness of IADS suppression on 'night 1', the F-35's approach to dealing with IADS renders LF effectively redundant. If you strip away LF's usefulness in avoiding IADS, it's fuel-inefficient, increases vulnerability to low-tech threats (AAA / MANPADS), constrains the effectiveness of unpowered weapons such as PW4, makes reconnaissance and laser designation more difficult.... etc!
If F-35 LF is needed at all, it would be for things like shows-of-force in support of ground troops or visual aiming of weapons at low-level beneath cloud [which, in the fixed-wing CAS world at least, is already being steadily replaced by the delivery of GPS-guided bombs from medium-level against coordinates provided by the FAC; no LF required]. Shows of force and low-level weaponry are not particularly 'core' F-35 business, which is why I believe LF will be a long way down the training priorities list.