You have good substrate, so dont worry about ferts unless the plants show yellowing and other problems. Go ahead and stock new fish slowly. You can go onto aquadvisor and check to see if theres any fishes you want. After that, watch your plants grow and your fish thrive. Change water every week and you should be fine. Look into aquascaping if you want to get more advanced into the hobby.
Sent from my XT885 using Tapatalk 2