I think everyone is slightly hysterical about the op tbh :-)
She's chosen a breed of cat, so no point banging on about her not getting a rescue cat
Her DS liked a colour cat she wasn't really wild about, ok, so she has a preference, why jump down her throat! She has a preference, so what... It's not a rescue cat, she's paying for this cat- you get to choose the colour and the cat.
No point derailing the thread about cat breeds Vs rescue cats. Or private schools Vs state schools or anything else that gets you going!
Her DS chose a cat who was a little better at being picked up at this age... So, would you think he should have a spitting slasher, or a shaking, timid kitten?
Let's keep our perspective here- her DS has a short fuse, and this animal will help him be calm and soothed. No need to bang on about how she is somehow using the cat, or some such nonsense- all pets are therapeutic, or we wouldn't have them.
Op I do think you may find that the kitty your DS chose might well become more active once he's not with all the other sibling cats! You may find that he's a bit more lively when he's alone, and for that reason I wouldn't get the colour point as well.
Best of luck with your kitty, and your DS. I'm absolutely positive you'll all fall in love with this little tabby snuggle puss.