Teenage striker Parkinson, who joined the Magpies' youth set-up at the age of seven, made his maiden league appearance for his boyhood club during United's 2-0 defeat against AFC Bournemouth in November, featuring as a second half substitute at the Vitality Stadium.
Ndiweni, who joined United's Academy from Newcastle City Juniors in 2016, and Diallo, who arrived on Tyneside from West Ham United in October 2022, were both handed their first Premier League outings during Newcastle's 4-1 victory against Chelsea, featuring in the final minutes at St. James' Park.
The Academy graduates’ achievements were recently recognised by the Premier League as they received a commemorative Debut Ball apiece at the Magpies' Little Benton Academy.
Introduced in 2015-16, the memento is given to all homegrown debutants who were developed at the academy of a club in English football for three years or more at the time of their first appearance.
Parkinson told nufc.co.uk: "I'm over the moon to have the ball as a keepsake to always remind me, not that I'll ever forget, of the occasion.
"For now, I'll be keeping it in my bedroom but when I move into my own house, I'll have a place to put it alongside my match-worn shirts.
"I went to warm up and we were losing 1-0 (against Bournemouth) at the time but the manager wanted to change something and bring on some fresh legs. I did well in training the few weeks beforehand and I thought I impressed him in pre-season to build up that little bit of trust.
"When he called my name, I was buzzing. I was a little bit nervous at first but when I stepped onto the pitch, all of the nerves dropped and I was thinking a dream had came true for me."
Ndiweni added: "I've worked so hard over the last eight years I've been here and it's always been a dream to play in a Premier League fixture for Newcastle United. Ever since I've grown up, all I've known is Newcastle so to be part of the first-team and for that to come true means everything.
"A home debut and a win against a top side with lots of top quality players felt really good and to be part of the squad for such a big victory in the season was great."
Diallo, a representative of England from under-15 to under-17 level, said: "I'm very pleased to have received the ball as not many people get it. Firstly, I'd like to thank the club and the manager for giving me the opportunity to play at St. James' Park and it was a very good win that day against strong opposition so it was something to be pleased with.
"When I visited the stadium before signing for the club, I knew I wanted to play here and especially in front of a sold-out crowd.
"It's good to get that opportunity because we work hard all week and you are wanting and fighting to be in the squad so I'm happy to achieve that."
Newcastle United Academy director Steve Harper added: "It is a very proud day for everyone associated with the academy to have three lads making their Premier League debuts for Newcastle United.
"It is something they'll never forget and a real testament to Ben, Michael and Amadou's hard work along with the efforts from many staff members within the club's academy."
