Rescued a tank and some fish from a family member

When I saw the condition of a family members tanks I jumped on the fact that they were moving a few hours away in a few months and offered to take the tank off their hands. They had a 20gal, filled with walmart brand blue gravel, a bunch of cheap decorations and some plants, which I have included in the imgur gallery below. In the tank she had 1 bleeding heart tetra, which was apparently one of many different kinds of tetras she got, but "None of them would school, they all just died" (I think she was trying to school one of each kind of tetra together).

She also had a betta bowl with some glofish and a long fin danio in it. Only 2 of the glofish and the danio were still alive, so I offered to take them off her hands too and told her about cherry shrimp, which I sold her on as being "Much more low maintenance than fish" and when I showed her pictures of them she agreed that they were "Super cute" and she will convert her betta bowl to a nano shrimp tank (With me instructing her the entire time and sending her a small piece of drift wood with java moss and a moss ball for it).

So I've got this tank, a heater, a filter, a dying tetra, 2 glofish and 1 danio. I picked up a few gallons of distilled water and am using the filter that was already in it to cycle it as best I can to try and save the fishes. I took most of the gravel out of the tank (Putting some in a cheesecloth pouch and hanging it from the side of the tank to keep extra bacteria, of course) so it's bare bottom until I can go to petco tomorrow to pick up some ecocomplete. There is also no lightbulb in the hood, so I will need to pick up something in the light department. Luckily I was planning on starting my first planted tank soon and have already been growing java moss in a betta bowl I picked up on the cheap.

Any advice on how to salvage this tank/these fish? I am pretty positive the tetra is a lost cause, but the glofish are actually pretty damn excited to be out of that bowl. Also, any ID on the plants? I have like 5 handfuls of them.

Heres the gallery.

EDIT: The tetra kicked the bucket. I found him after all the water cleared. Poor guy never stood a chance.