The alfalfas pellets (and meal) that I use have no salt added (some 'brands" do, and if so, it's always marked on the bag), "test out" at 3-0-2, as far as fertilizer value. That would mean that in 100 pounds of pellets, there is 3 pounds of nitrogen.....but, being a totally organic product, it is "slow release', or, in other words , it's released gradually as the pellet 'rots away"......and, since the bacteria that digest (rot) organic matter need nitrogen to do their job, most, if not all ,the three ponds is "tied up", and not available to the plants. The big benefit to the alfalfa is the "natural growth hormone"(and without a google search, I can't remember the chemical name
) that 'helps" give other plants a "growth boost"...it's 'documented" that iris, roses, daylilies, and mums benefit from it (and probably other plants as well, but I can find no references). This "growth hormone" is what makes alfalfa such a good "cover crop"(along with it's "nitrogen fixing " properties), and such a good forage crop (animals know what's good for them !( except the turkeys at Rob's house
). As to "luring" rabbits, or other "critters" into the bed, I have seen no sign that the alfalfa is a problem. As was stated earlier, as soon as the pellets get damp, they fall apart, and as I usually try to "scratch them into the soil surface', or mix them into the 'hole" at planting time, they aren't really available for 'rabbit food', anyway. I would say the thing to do ,is give them a try, at least on a few plants, and see if they seem to work for you.I would also recommend that before you do very much ,as far as soil "amendments", that you have a soil test done. It's pretty hard to "add what you need' ,if you don't KNOW what you need !