1 angel fish would be a bad idea since need to be kept in groups of at least 5 to avoid stress and dominance problems.
as for the plants, try the "simple" plants first like lettuce or spinach.
as for the pump, something that will pump water at a flowrate of aprox. 7 gallon at one feet.
as for the waterchanges, you would still need to do them to remove any protein/hormones produced by the fish.
but all in all it would be a feasible system if your tank isn't heavy planted
as for the plants, try the "simple" plants first like lettuce or spinach.
as for the pump, something that will pump water at a flowrate of aprox. 7 gallon at one feet.
as for the waterchanges, you would still need to do them to remove any protein/hormones produced by the fish.
but all in all it would be a feasible system if your tank isn't heavy planted