How are they when you pick them up and place them on your lap? That might be a starting point for them getting used to being handled, very brief handling, and having some treats on your lap. Have them in a handling position as they sit on your lap, as well. Allow them to bolt if they want to. They may bolt at first, but eventually could warm up to the idea of being held if you're persistent enough. But keep in mind some cats just plain don't like it, no matter their background with people and no matter their trust in you otherwise.
I can pick up all my cats, all were once semi-feral or feral. Blaze was a feral kitten and loves being carried around, Blacky was a semi-feral cat that took a year until she'd allow me to pet her and she doesn't mind being carried around either, at first I had to get her used to the idea of being handled, it started by her realising that sitting on laps was an ok experience. She's more interested in having her front paws over my shoulder as a means of being carried. Jasper was semi-feral four months ago, in the first two months picking him up was not possible. I likely have a scar on my hand from him spinning around and biting me when I put him back on the ground... these days he doesn't mind being picked up and walked around with but would rather be put back on the ground. We're working on it... but he's come a long way.