Plenty of people use sand and have great success. Sand is my preference. A organic soil base is helpful.
Since you have the sand in an established tank I wouldnt mess with it. Any larger plants you add can be feed with root tabs. Make your own or buy.
is always helpful. There is a sticky on the basics if you need it.
The plants you mentioned can grow fine without it. Anubias species, crypts, hornwort, wisteria, are a few to get ya thinking.