Vinegar gets a lot of buzz as a miracle gardening product. Manufacturers claim the product kills weeds, fertilizes the soil and even combats plant diseases. Vinegar is an acid and can cause damage to plants, although it probably won't kill flowers. Just the same, use it with caution in the garden.
The application of salt dries out the plant and can cause root burn, which inflicts damage on the root system, preventing the roots from carrying nutrients and water. Large amounts of salt can remain in your soil for months and years, preventing the growth of new plants and killing nearby plants.
Yes but if you get it on the flowers they will die https://www.craftylittlegnome.com/permanently-kill-grass-weeds/
Only if you want to kill your plants and make the soil barren.
For your use, just try straight vinegar. The vinegar will dissipate quickly to not ruin your garden soil while salt stays there. Be cautious to ONLY put vinegar down at the base of the weeds so your plants are OK.