VSion is all about rushdown, rushdown, rushdown. So the whole idea to playing her is by keeping up the pressure. You want to pin them to a corner for her 4k - 5k
She does not have that many great pokes imo from neutral situations outside of her fast dash, jA and jC, so you need to be more cautious in your approach. The key is scoring a knockdown and work on your wake up game.
I don't think there's a specific game plan / approach to Kohaku. You just have to watch out for her range (jB, jC, 5B, 5C, 2C). Since Vsion's range is not all that great, just be cautious of your approach.