From all I’ve read re: fasting, it’s best to avoid until you are more or less done growing. Regular intermittent fasting is almost certainly fine so long as you are still regularly eating nutrient dense foods - this is still a very effective weight loss strategy. I’d say it’s safest to focus on dialing in that diet and then do some regular HIIT. Things like sprints, whether running or rowing … these are powerful stimuli for the body to adapt its composition to encourage more lean mass and less adipose tissue.
Nobody knows
Nutrient deficiency and long term low calorie diets will stunt your growth. That is well known and well studied. I.e. eating sporadically with a low total daily calorie count.
There have been no studies on long term fasting and growth.
Its possible that it’ll fuse the skelleton biology thats responsible for bone growth but nobody has tried it.
Its also entirely possible that it wont fuse and the increased human growth hormone and insulin sensitivity will lead to extreme accelerated growth.
Nobody has tried it and written down the results yet
There’s no way of knowing as individual growth varies. Thought I’ve never met anyone who suddenly had a 3 inch growth spurt past the mid teens. I’m sure I stopped getting taller at 16 (I’m a woman). One thing that’s for sure is obesity is hazardous to your health no matter how tall you are.
I’d say try it and see. Being 5’9 for life isn’t the end of the world.
If you go the dry fast route I might suggest a five day fast, seven day if you can make it. That will allow a reasonable period of autophagy and cleaving fat cells. I know you know this, but I’ll say it anyway, you will lose a lot of water weight that will come back - as it should.
I’d also really stress that you have a very intentional refeeding plan in place and then once out of refeeding focus on a way of eating that fits your new goals. By intentional I mean don’t overload with empty carbs and sugars early. A bad refeeding plan can wipe out all progress you will make in a dry fast from a weight management point of view.
As for your age, one dry fast a year shouldn’t create any chronic problems (not medical advice, just observation) but everyone is different, so listen to your body
I’d say go for it, but as you are so young, I’d not do more than one extended dry fast per year.
Edit: cleaned up typos