A friend of mine had a Senegal bichir. Not sure if I would go for this combo, but he had 2 yellow labidochromis (Malawi cichlids), a green severum, and an archer. Yellow labs are African cichlids, severum is New World cichlid, archers are brackish (correct me if I'm wrong on that one)---what an odd assortment, I know, but with plenty of rocks, caves, and driftwood all got along "fairly" well for many years.
edit...I would absolutely stay away from sand from a pond. Many "critters" have eggs that lay dormant in the sand, hatch out during next heavy rainfall (or upon being added to your aquarium). Don't risk it. Play sand is cheap but dirty, need to do a lot of rinsing in small batches. Pool filter sand would be better, many of the impurities and clouding agents are removed. Costs a little more than play sand, choice is yours.