If Ting is able to get her senior TES mins at Tallinn Trophy (which she has already been assigned to), then she will be eligible to go to senior Worlds. I think the fact that USFS is sending her to a Senior B demonstrates that they will give it to her if she performs well.
If she places 2nd at Nats (or 3rd if Alysa 3As her way to the top), given that Bradie will be 1st, the fed will highly consider sending Ting to Worlds given her high scoring potential that is probably equal to Mariah's. Even though Ting is competing on the JGP, she can post high scores (as evidenced by her 70+ SP score that some other American ladies have yet to achieve this season). Her recent performances at Eastern Sectionals (181 total score) is very respectable. Judges love her elements, giving her high GOEs, as well as high PCS.
There is a precedent to this. At 2014 Nats, Polina Edmunds had been competing on the JGP and had never competed at a senior international competition up until then. Her first senior international competition was the Olympics. Thus, it wouldn't seem odd to send Ting if others don't perform as well.