If you want to add activity to the tank, barbs, characins and rasboras are a better idea than cichlids, as in most cases, they offer more activity and less issues, even if they (usually) have less character.
Love the video. That was a great idea doing a time lapse like that. If I had a tank that looked half decent, I would do the same.
He probably meant snakeskins. Great fish for this tank, tough, gentle and plenty of personality, even if they do like to eat plants a little, as long as you don't keep any nastier cichlids, which the OP doesn't want anyway. IMO chocolates are a bad idea no matter what. They are very delicate, require very acidic and stable water, and are easily bullied, and they are rare and expensive. A perfect fish to keep if you want a challenge, not an addition to a community tank.