If you author a disc with a progressive stream, only a player’s progressive outputs will do. Also you must have a monitor which is capable of displaying progressive. If you do not have a progressive player, the player itself add the 3:2 cadence for interlaced outputs. If your footage was originally shot and edited progressive, then your disc should be as well. No need to worry about which player will play what. All players will playback a progressive stream, it just depends if it has P outputs. Never deinterlance or convert for DVD.
Depends on what you mean by professional, but most Hollywood titles are progressive. Not sure the ratio of progressive and non-progressive set tops.