Hi me again umm I'm not sure what carpet plants would do for pea gravel. The tank is good by the way the four tiger barbs problem will be solved getting more soon
It would be a good idea if you could add some root tablet fertilisers, you push these into the substrate so the roots of the plants get nutrients and a liquid fertiliser to put in the water so the plants can take it in through their leaves.
It should do but if you add root tabs it will really help. How you plant it will make a big difference too. When you plant it break it up into small clumps and plant them all a cm or two apart