personalities (like all cats, eh?).
Found that generally, as mom goes, so goes her babies. Of my last litter of four feral kittens, the three males were sweet as could be; the lone female (also the last born) never accepted handling. She stayed close to her mom at all times. They lived with me for 18-20 years...died of old age.
Build trust. Found that handling several times a day worked well. I'd set them on their back in my lap, tickle tummies and massage their feet quietly as I watched TV. The feet and the sides of the face contain scent glands, so the kittens and I were exchanging our scents as I rubbed them.
Currently have a single male feral cat that I took in about three years ago. He's neutered, of course, but our first year together was a bit difficult. He remains, aggressive. His little "temper tantrums" appear to occur when he's not getting my attention. He'll suddenly run up behind me and bite or scratch me. I ignore it, and after he's settled down, I get my kitty brush and give him a nice soothing rub-and-brush session. His behavior returns to sweet...until the next time he feels ignored again.
Good luck. You're a kind person.