Waikato's Ratcliffe, who has just graduated with an economics degree from prestigious Princeton University in New Jersey, is No 30 with a best this year of 69.24m at New Haven, Connecticut last month, and is chasing a 71m throw for a B standard, 72m for an A.
Palmerston North's Langton-Burnell, on the back of his personal best 82.44m at Porritt Stadium last weekend, is No 23. His B standard is 83m, the A 1m further.
Hall is likely to be offered a trip to New Zealand's training base in Cardiff ahead of the worlds.
There will be chances in leadup competitions to get one of his two target marks.
Langton-Burnell, heading for the Oceania champs in Suva at the end of this month, is in a similar situation, and a trip to Cardiff is in the offing while Ratcliffe's situation is slightly different.
The Glasgow Commonwealth Games silver medallist, whose personal best is 70.75m, put in a disappointing 65.25m at the NCAA championships last weekend and will stay at Princeton and target some events to aim for the qualifying standards.
The thinking is if she can put up a 70m throw, she'll also be in line for an invitation.
ANZ have a policy for younger athletes that effectively they will give them a helping push if they're trying to qualify for the first major international championship. Once they have done that, then they are on their own, so to speak.
"We will try and support them, especially in the first year of an Olympic cycle," high performance boss Scott Goodman said.
That might, for example, extend to a single B qualifying standard or pushing their case via the roll down system.
So far New Zealand have a team of eight going to the world championships from August 5-13 - Tom Walsh (Christchurch, shot put), Jacko Gill (Auckland, shot put), Angie Petty (Canterbury, 800m), Camille Buscomb (Waikato/BOP 10,000m), Zane Robertson (Waikato/BOP, 10,000m), Eliza McCartney (Auckland, pole vault), Joseph Millar (Waikato/Bay of Plenty, 200m) and Quentin Rew (Wellington, 50km).