The versatile Headley can operate as a left-back or left-winger, while Austerfield, who spent the second half of the 2021/22 campaign with the Sulphurites, is most comfortable anchoring the midfield.
And it was the latter's experience on loan with Town that persuaded former Millwall man Headley to swap the Championship for League Two, having recently agreed a new two-year contact at the John Smith's Stadium.
“Josh had so much good stuff to say about the club," he explained.
"He said it’s a good experience, that the changing-room atmosphere is great and the backroom staff and fans are excellent, so it’s all positive.
“I’m looking forward to it, I’m really excited to play in this league with this club and can’t wait to see what happens this season."
Born in Southwark, London, 20-year-old Headley previously turned out for Millwall’s academy before making the switch to Huddersfield at the age of 17.
He has since had loan spells at Bradford Park Avenue, Hyde United, Welling United and Yeovil Town.
"Jaheim we watched last season and we know his qualities are his strength and his pace, he’s a very dynamic and powerful left-back," Weaver said.
“Paul Thirlwell and I both earmarked him early on as one who, if we could get him, would be so exciting. If we can get the best out of Jaheim, he’ll be hard to stop."
Twenty-year-old Austerfield made a total of 11 appearances for Town last term and impressed towards the back end of the season with some composed displays in the centre of the park.
Now, he says he returns to North Yorkshire with a point to prove.
“I want to come back and show that I am a better player than before, I loved every minute here last year whether I was playing or not," Austerfield said.
“The gaffer and Thirs [Thirlwell] believe that I can keep improving on what I showed at the end of the season. They wanted me back and that was a big positive for me.”
On his decision to re-sign Austerfield, boss Weaver added: “Josh’s attitude was absolutely first class and he just got better and better throughout his loan last season.
"The last five or six weeks he just seemed to go from boy to man and absolutely excelled on the pitch.
“He’s gone away for the summer and got stronger in his physique, he’s over six foot one and a real ball player, so it’s a massive result to be able to bring him back in.
“Even good team players should have individual aims and he’ll be looking to be one of the best central midfielders at this level without a doubt next season."
Austerfield has taken the number 17 shirt for the coming season, last worn by recently-retired club legend Lloyd Kerry, while Headley will wear number 15.