I keep my sev with a number of smaller south american cichlids and they get on perfectly. He did contribute to the death of a larger male though....
A friend also keeps one with smaller community fish and again, he gets on perfectly.
I guess it just depends on the fish, but I would say it will be fine with the angel.
I have not tried my sev with plants, partly because I cannot be bothered with plants and partly because chances are that he would eat them. I woudent try it. You could however try java fern, supposedly not many fish eat it but ive never tried it.