The Legacy (comics) stuff takes place 140 years after Yavin
The Legacy of the Force (books) takes place 40 years after Yavin
Also, Cade doesn't use the Skywalker name, dropped it on purpose. He is a bounty hunter. This should be an awesome series because they don't have to worry about the big three (LS, LOS, HS) and have brought the family back to one son. I hope the books (9 total) wrap up the timeline for the Solo twins, Ben, big three, Mara, etc.
The fact the comics have jumped a hundred years means Ben must have had a son or two and then that child(ren) had at least one.
If you miss this series, you will miss a lot of cool Star Wars stuff, because that have put it in the hands of two people who care about making good Star Wars stories.