I always wanted two kittens, from the same litter. We went to visit some British Shorthairs and discovered DS has cat allergies - totally blocked nose and sneezing writhing 30 mins - confirmed by positive allergy test at dr. Odd though, because he's been to sleepovers with people who had cats and had no problems and we'd had a cat before and he'd had no problems. I looked up hypoallergenic cats and discovered our previous cat was highly likely to have been predominately Siberian (he was adopted/rescued and I just chose the cat I loved and who loved me).
So I found a Siberian breeder and we eventually got one kitten (one the breeder said was a bit of a loner - we had to wait a few litters for that). DS has had no reaction at all. Kitten is full of energy, great kitten. He's 4.5 months old and we've had him since he was 9 weeks.
I have this niggling feeling though that he shouldn't be a single cat, he should have another cat with him, because it's not fair to him. When he's playing I can see how another kitten could be having fun with him doing kitten things.
I could go back to the breeder no problem. But I just can't tell now if he'd be happy (or grow to be happy) to have another cat in his space. He's an indoor cat and a second cat would be too (this is not how I've had cats before, but circumstances are different). It would also involve a lot of stress because we'd have to see if DS has a reaction to the cat or not (hypoallergenic just means less allergen, not no allergen and every cat has slightly different amounts). That means due to Covid (I'm not in the U.K.) I'd be bringing the kitten to our home to test DS' reaction to it over a period of up to two weeks. My gut feeling is it'll be fine (DS' reaction came when in a smallish room with 9 kittens and 2 cats - some British Shorthairs and some British Longhairs), but there's that risk. I don't want to be unfair to the kitten and I don't want to deprive my cat of a playmate if he could have one!
He's very attached to me which is fine because I'm around a lot for now. In a year I will be out more, but one of the kids will be in more.
We don't live in a massive place but there is space for another cat (only one more).
The kids would love a second cat.
So that's all the info. I'll post a photo in a moment. 
Do you think I should be looking to get a second kitten? Btw I would only get one from the same place as he came from.