Welcome to the forum!! As far as your stocking list goes, I personally feel that it's overstocked for a 5 gallon. I'm not too sure about the sparkling gourami, but gourami's in general including the dwarf strains need at least 10-20 gallons. Otocinclus cats are pretty sensitive to water quality, and the danios are a schooling fish, and usually with schoolers you want to count on having a minimum of 5. Why don't you up the tank size to a 10-20 gallon? They are not that much more money, gives you more room to aquascape, it's a lot easier to control water quality, and if you went with a 20 gallon you could stock these fish with a little room to spare.