A paradise fish would be great in there and they have huge personalities. They do jump and quite high, I often hear a splash when one gets startled so definitely lower the water level a few inches if you can't cover the tank it any way. If you could get some sort of mesh to act as an anti jump barrier it would be a good idea.
I second that. They truly are jumpers. I see no sense in keeping fish I worry will go on suicide missions.
Mine disappeared one day. I found her a few days later when my pet rabbit found him under the sofa!
Will adding a top complicate your plans for your tank?