I know you probably will but try looking up videos of the tetras so you can see what they look like when they are comfortable and showing their true colors
Talltrees stocking looks good but get Bolivian Rams rather than Blue Rams as they will deal with the temperature range of the other fish a lot better. One of the other dwarf cichlids might be an option as well...
But I have to agree with some of the latest comments - 2 weeks without a water change is no reason for fish to die. Through no fault of my own I have had to leave tanks that long without water changes over the years and not had problems....
Wills
*edit - did you leave a feeding block in the tank?
No. My grandpa fed them. I'm not sure why but he gave them goldfish flakes. Could that be the reason? I did some big water changes and cleaned the filter and the fish look a lot better. And no, I sold the kuhli loaches. I just haven't changed my sig yet.