"Is he still alive, and if so, is he still playing?"
Burt is very much alive and well. I know that whenever Barry Harris is in town, he usually plays with him. He also plays frequently with Donald Walden and his group. I've had the pleasure of watching him perform with both BH and DW a couple of times and really enjoyed his energy. From what I understand, he recently (within the last couple of years) moved back to Detroit from NYC.
Gallert can answer the rest of your questions.