I believe the biggest one is around 12 to 14 cm so that is something like 5 inches. I do have one picture and a video of him/her as well. The knife shaft in the picture will give some perspective about it's size.
Yep. All the plants have their roots hanging in the tank. Easy to maintain houseplants as no watering is required.
I do not know the English names for each of them but the latin names are Scindapsus pictus, Spathiphyllum wallisii, Epipremnum pinnatum and Monstera deliciosa.
I have 3 x 70w metal halide lamps attached to the roof. Below is an very old picture when I first bought the lamps. They're actually meant for lighting up some store windows but works fine for aquarium too.