The "oregano" plant is I believe Hygrophila polysperma; it has that leaf structure and stem nodes. But I wouldn't insist if someone argues this.:lol:
The two swords I would move apart; they will get huge. They are most probably the "common" sword, Echinodorus bleherae in our profiles though as it mentions there this might actually be E. grisebachii. But they will grow to 20 inches in height and spread almost as far, so moving them apart will allow for better development. I have noticed that when these plants are close together, one often grows and the other is rather stunted. In your aquarium, I would leave one where it is and move the other close to the left side, about 4-5 inches in from the end wall.
With all these plants, and most being heavy feeding, I would dose Flourish Comp at least once a week. Weakening plants initially will not help them. Your harder water does contain the hard minerals, but these are not in Flourish in any significant amount anyway. What you will be missing are the trace minerals. These will occur from fish foods, but unless you have a heavily-stocked fish tank with multiple feedings per day, this is not going to amount to much plant nutrition.
By the way, the brown spots on the swords are iron deposits. This obviously occurred from their previous life; either too much iron, or insufficient calcium which causes plants to uptake more iron. The leaves will not improve, but as long as new growth from the centre of the crown is good there is nothing to worry about. I would leave the older leaves on until the new growth is significant; some nutrients are what we call transient, and the plant will shift them from older leaves to assist new leaves. Another reason to provide Flourish weekly; this prevents the plant from having to go this route if the nutrients are insufficient for new growth. Remember, plants will do everything they can to grow at the maximum level, until one nutrient is missing.