Son and Johnson are very similar in that they're both moments players imo. Can deliver the most important things in football (goals and assists), but often don't contribute that much outside of that in terms of overall attacking play.
Son is and has been creative if your definition of creativity is end product, creating chances. As Johnson has been when set up in the right situation.
That's not the only possible definition of creativity though. If people are talking about creatively combining with others to make or exploit space, or turning average possession under pressure into great possession through skill and dribbling I don't think Son is particularly creative.
Set Son up in the situations he thrives in and he's fantastic at what he does. But he needs that space to run into, space to get on the front foot and run at people or of course a chance to use his ball striking for a shot or cross.
But he's not "creative", he's fairly predictable in what kind of situations he's good in and what he'll do. He's just so good at it that even though people know what's coming he'll still succeed (or used to anyway). He's a creator, but he's not "creative" (by that definition of creativity). Stats for creating chances doesn't change that impression because that's not what all people mean by creative.
Moments players are great, if they're good enough at what they do, but too many moments players leaves a team unbalanced.