I would imagine that the EXL's would be softer on frets than the NYXL's or Pro Steel range but not as good as Pure Nickel - which was the type of strings around in the 50's and often associated with the warm vintage sound. The issue is that the 3 unwound strings are Steel which are likely to be harder than nickel frets but without actual testing and being provided with the material hardness measurements, its difficult to say how strings and frets would hold up and how that could compare with other strings.
Frets are an alloy too so it depends on what they are alloyed with and the percentages of metals will change their hardness. Its like needing a diamond to cut a diamond because of the hardness of the materials. Stainless Steel frets are very hard and why they ruin tools. The hardness value determines how materials will wear. If the strings are not as hard as the frets, the strings will wear more but as the difference between the hardness closes, the slower the strings will wear and more the frets will. At the extreme differences in hardnesses, the softer material (frets or strings) will wear much quicker than guitars that the frets and strings are more evenly matched.
Without having the hardness values though, you don't know whether certain strings maybe better on your guitar. The best bet is to monitor your guitar and see if you can see signs of fret wear and how much wear between string changes. If you think its wearing too much, try different strings to see how they wear. They may seem similar but the steel may not be quite as hard and you find that you don't need to dress the frets quite so often. Its also worth looking at the strings too and seeing if you can see any wear on the underside where they meet the frets - particularly in the areas you do a lot of bends/vibrato as that is rubbing on the fret. If the string looks like new and the top of the fret has some scratching or signs of wear, then you know the string is likely to be harder than the fret and require more frequent fret work. If the fret looks like new and the string shows some sign of wear, then you know that the frets are harder.
It really does depend on you the player. If you prefer the sound of a brighter string, then you may have to compromise on a string that causes a bit more wear on your frets than something like Pure Nickels which may not wear your frets at all - at least not to the point where you need to level and/or re-crown every year but not bright and zingy enough.
It seems to me that as we are chasing hard, strong strings that don't break easily and last longer between string changes, we are hearing more and more people complain about fret wear. It also seems to be that more and more people are chasing Stainless Steel frets - which can wear too by the way if the string is as hard but obviously not at the same rate as softer frets. PRS Nickel frets are regarded as one of, if not the best wearing nickel frets that polished can feel just as slinky as SS frets. String hardness though will affect wear....