Hayles, who scored a hat-trick in last weekend's 3-3 draw with Charlton Athletic Women, is set to line up for the Reggae Girlz against France on Friday, while Joel is preparing for a Women's European Championship play-off round double-header against Slovakia.
The Magpies' rapid rise up the leagues means they're now able to recruit international quality players in the Barclays Women's Championship but in 2002, Lynsey McLean became the first player to earn international recognition with United's women - although it came in unusual fashion.
"It was quite bizarre because I was only home from America for six months and I'd signed for Newcastle United," explained Falkirk-born McLean, who had started her footballing journey at the age of 12 with the Magpies between 1989 and 1996 before heading to the USA on a soccer scholarship.
"I then received a letter in the post asking me to attend a Scotland camp. Someone from over in America knew the Scottish national team manager and said they needed to give me a trial and see if I was good enough to play.
"I got the chance to go train with the Scotland squad for two days and was invited back, but obviously when you look at what the players have now, it was completely different back then. But it was still amazing."
Coming from purpose-built stadiums in America to run-down and often neglected facilities with Scotland was something of a culture shock to McLean, even if she was living out a childhood dream.
Ever since she could kick a ball, McLean had dreamed of being handed the official Scotland tracksuit and kit, although the FA did try their luck at getting her to switch allegiances.
"At the time, the facilities weren't particularly great, but it was better compared to what I was used to," she explained.
"When I was little, all I wanted to do was play for Scotland. The funny thing is, I did actually train with the England under-21s before I went over to America, which says a lot because I'm not English.
"Obviously, I would have always picked Scotland over England, even though the latter were a better team, because I'm very patriotic and I was over the moon to play for my country.
"I got the call up when I was back in the UK and playing with Newcastle, obviously not full-time so I'd also work at Sainsbury's working on the checkouts.
"The shifts were bizarre hours which made it difficult to remain committed to football."
Midfielder McLean's debut was not in any dead-rubber friendly encounter, but the 2002 Algarve Cup against Canada.
While Scotland failed to get past the auld enemy England, it was a tournament to remember and McLean had a message for the current crop of international stars in the United squad.
"I was extremely nervous because my first cap for Scotland was when I got called up to the Algarve Cup in Portugal, which was amazing," she said.
"I was buzzing to finally pull on the shirt and show everyone what I could do. It was pretty indescribable, to be honest - it was a surreal experience.
"Not everybody gets the chance to represent their country and it might turn out to be your one and only opportunity, or it could be the first of many. So you've got to go out there and enjoy every minute representing your country."
McLean won four caps before heading back to the USA later in 2002. Returning to Tyneside two years later, she rejoined the Magpies between 2004 and 2006 before winding down her playing career due to work commitments.
It's not just Newcastle United who have experienced extraordinary growth in the women's game over the past few years, but the sport as a whole has gone from strength to strength.
Women's Super League games have attracted crowds of over 60,000, while the Lionesses winning Euro 2022 was a huge moment which saw an increase in girls taking up football.
And trailblazer McLean is only too happy to see the players of Newcastle United and other women's teams paving the way for the next generation.
"It's been fantastic and so good to see because I never thought when I was playing all those years ago that there would be these sorts of opportunities for women in football," she added.
"The game has just spiralled and it's fantastic to see. I've got two little girls and if one day they want to be footballers, then they know there's that pathway.
"Back when I was playing, if you said you played football as a girl people sometimes looked at you horrified, but now it's widely accepted that girls do play football and can be very good at it.
"I would have given anything to have the sorts of opportunities that the girls have nowadays when I was starting out, but it's fantastic to see."
Newcastle United Women's next home game sees them return to St. James' Park to take on Southampton Women in the Women's Championship on Sunday, 17th November (kick-off 2pm BST). Tickets are on sale now from book.newcastleunited.com.