Take the Congruent Tennis challenge....

For #2 I'd expect for most wide balls you would have more reach and ability to cover in the closed stance for the 1 hander with a "step down, come around" and would likely only go to open stance if you got there quite early on a deeper ball in the Rally zone. In the end, I believe it is more about personal preference as to how to end up at contact based on your confidence in your ability to execute the shot you intend to make. You should know what stance you prefer at that moment, but also get some practice in the backup stance. Players are amazing in how they can often get to the preferred stance even when time is tight if they are clear in their intent.