New Horse conformation Advise

He has a light/weak hind end with the SI joint, pelvic girdle placed so far back.
That "bump" is where spine and hips join = motor.
When so far back, yes, steep croup, less motor, less hind-end getting under himself.
No, in my opinion he will not outgrow that deficit and will forever be at a disadvantage in scope doing many activities and yes, his straighter hind legs seen in the last picture of his left hind is accurate of his normal stance.
You as a rider will take a pounding on your body as he will on his too.

He is posed and not square on 4 in that picture...
He's cute, but has some weaknesses in his build as others have mentioned.
3 years old, he is what you see for the most part...only going to chunk up with maturity but bone frame and stance is what it is going to be.
🐴.... jmo...

I see extension, now you need to see collection and how he moves doing that if you want a all-around type horse.
I look at his head carriage in the picture provided and don't know if that meets your needs or not...
As a horse with a under-powered hind-end, on tough courses he may have difficulty if you truly tax his ability.
The hind-end scares me honestly in elevating the risk of catastrophic breakdown of tendons from the push you need to do your activities.
The neck bothers me too when you refer to doing 1 meter jumping with him... its so important the body is balanced for the bascule you need in the air to clear cleanly jumps of that size, especially as the horse tires. With such a high tie-in it limits what he is going to be able to do...short thick necks limit agility...you need agility to jump those heights. He is going to be heavy on his forehand nearly constantly.. Add the weak hind-end...
A PPE with a lameness vet specialist is where I would go if you go see and really like in person, then shake out all the dust and fine-tooth comb look for those deficits and failings. You need a vet who can predict growth outcome with where in their development the animal now is.

I'm sorry, the more I look at him and go back and read what you want him for... go look, but stop looking at his color and look at him...
You don't ride pretty, you ride functional. He's front end heavy and hind-end weak is not a good combination.
I think I would pass or your goals may need change done as not sure this guy can physically do what you desire...he may have heart and try, but if he not have the body to allow it...you're stuck. I also can see him breaking down, being lame from strains and ruptures in time with demands on him made.
He is a pretty color, but you have to view the animal, not the pretty color he is...and he is not built well. Truth.
sorry.
🐴...

I think your questions really need to be put to a vet with the animal in front of them.
Fat, skinny, muscled or not the bone structure is what it is and the muscles, tendons and ligaments are going to be aided or hurt by the bones structure underneath...the frame.
If you build a home on a lopsided foundation it can only withstand so much before failure starts,...same as our horses.
You've alluded to having some breakdown issues occurring with your aging horse...and can see similarities in build I'm sure that may be contributing factors.

I also don't know what are the breed specifics for the cross this horse is.
But a horse is a horse and my comment was for "a horse" and would be said for any animal no matter its breed or bloodline.

One other observation I had and forgot to mention is the horses right hind... that hoof and angle not match the other rear nor the fronts...and there is usually a pairing. I hesitate to say club because it is a hind and honestly I've not ever seen a club behind, don't know if that is such a thing.
If, if I saw that on a front hoof I would call him club-footed...and that too for me, no -go as clubs can be limiting in the pounding it takes and a closer proximity of the hoof interior bones and how they can rub to each other with straightness and narrow commonly seen in my experiences mainly with OTTB..

He is to cute to not go see.
But you need to see with color-blind eyes so you see the horse, not his shiny golden coat.
Let the vet help to guide you cause they are far more trained in things present and what the potential it tells of to come.
For a quick flip....not sure the $ return will be as much as you hope for and as said before, if you see where he lacks so will others and that hurts you on sale price and ease of making a sale.
🐴...