Very nice topic!
As a few people have stated correctly the Egpws system uses actual flap (not slat) position to determine whether it is configured for landing. So in the case of Blue HYD Remaining the procedure calls for EGPWS flap mode off to not get a nuisance warning on landing.
Making an approach with flap lever in position 2 or 3 will not make any difference to the slats actual position for landing BUT it does make a huge impact for the Go around...the approach is already being flown very close to VLS but now we must consider in the event of a Go Around the Gear now remains down (gravity extension), no use of the Stab trim available as this is powered by Green and Yellow HYD systems (so now a positive force must remain on the side stick to follow the correct pitch attitude safely as we are in DIRECT law) and also remember we have zero protections now also. VLS and VSW are very close on this kind of approach. Basic aerodynamics to conclude this really nice topic...Making an approach in config 2 then innitainating a go around and moving the flap lever up one stage in this condition would not be a wise idea as this has a good possibility of a stall.
Hope that is fairly clear and am happy to concede defeat on any of what I have stated above.