Entrepreneur James, 36, is the younger brother of the Princess of Wales, while French-born Alizee is a financial analyst.
HELLO! takes a look at the ways that James could follow his sisters' parenting lifestyles.
Growing up in the countryside
James, Kate and Pippa grew up in the quiet and picturesque village of Bucklebury, Berkshire, and it seems they all want a similar upbringing for their children.
While William and Kate were once based at Apartment 1A at Kensington Palace, in summer 2022, they moved to Adelaide Cottage in Windsor.
Similarly, Pippa and James swapped their £17m Chelsea townhouse for a sprawling countryside property in Berkshire – close to Carole and Michael's home, Bucklebury Manor.
In 2021, ahead of their wedding, James and Alizee also ditched their city pad in favour of a rustic countryside property in Berkshire.
The Middletons are renowned for their love of the great outdoors and the county offers the opportunity for long walks in country parks, visits to farms and wildlife reserves, and local markets and fairs.
Close family bond
The three Middleton children are incredibly close to their parents and all have worked for Carole's former business, Party Pieces, at one point or another.
We've seen Carole and Mike on grandparent duties for George, Charlotte and Louis, when William and Kate have been away overseas or during public engagements, such as the King's Cup regatta on the Isle of Wight in 2019.
When Kate and William were first-time parents with George in 2013, they stayed with Carole and Michael during those first few weeks. And no doubt James will find it reassuring to have his family close by during the newborn stage with baby Inigo in particular.
In a sweet Mother's Day tribute to Carole in March, James shared a personal snap and wrote: "You make my world go around. Happy Mother’s Day to all the mothers out there and especially to this one."
James has previously spoken about how he and his family hope to become fully self-sustainable as they restore their Berkshire farmhouse.
As well as their six dogs, James and Alizee share their country home with ducks, goats, hens and a beehive – from which they've been producing their own honey. Take a look in the clip below...
Like his brother-in-law William, James is passionate about the environment, even down to his accessory choices for baby Inigo.
James and Alizee were spotted pushing their newborn in a Silver Cross pram – strikingly similar to one Kate had when George was a baby.
The design has since been discontinued so it's possible that its been in the family for a while.
Similarly, James also sported a BabyBjorn Baby Carrier in the first precious snaps of baby Inigo.
The baby carrier could well be over 20 years old. It is BabyBjorn's original style in 'City Grey', a bestseller in the early noughties. The baby carrier looks to have been washed dozens of times due to the faded colour - could it be a hand-me-down from his family?
William and Kate have also used family hand-me-downs for their own children over the years, with Charlotte seen sporting a sweater that once belonged to George, and Louis wearing one of father William's outfits for his first Trooping the Colour in 2019.
What's next for Harry & Meghan? Find out on the latest episode of HELLO!'s A Right Royal Podcast...