@Rowen32 Not who you were asking, but having had this exact scenario with my 2yo this morning (for an activity not school), the "natural consequence" is that he doesn't get to choose what he wears.
I gave him a 2 minute warning with a timer that it was time to get dressed. When the timer went off I showed him 2 tops and he chose one (crossly but he did it) and we put it on. Did the same with some trousers and he rejected all of them. I said something like "I've asked you to choose and you're not able to, so I'm choosing these ones," sat him on my lap and put them on him. He wriggled and complained and fussed, but then went happily back to playing until it was time for the next task.
I think some of that is gentle parenting and some isn't but I'm not particularly bothered either way. I use a lot of routine to scaffold getting ready in the morning, and right now I spread out tasks he doesn't like (dressing, tooth brushing, putting shoes on) so that he gets time to play in between. I have a timer so that his choice is "now or in 2 minutes" and neither of us get drawn into "just one more" or "I need to do ..." And I follow through and do the thing when the timer goes off. Those things aren't explicitly gentle parenting, but aren't necessarily inconsistent with it either.
What is perhaps not gentle parenting is that I absolutely follow through with the task even when he kicks up a fuss, rather than spending ages trying to convince/persuade him to do it. I do it calmly as much as possible, I might make it a bit silly, and if there is something that is often causing a lot of friction and getting us both frustrated and angry (tooth brushing...) I try and find a different way of doing it. But part of the reason there was not much fuss about the clothes this morning is because when I say time to get dressed he knows I mean it.
I think where gentle parenting gets stuck is that people think that naming emotions and offering choices is all you need. With a lot of children it's not. And as the parent, you have the big picture knowledge about what is important (not being late, having clean healthy teeth, playing in a way that builds friendships, getting hated mundane tasks done), so you also have the responsibility to teach your child how do those things.