There isn't a lot of concrete info about the kids ages or houses, other than Scorpius, Rose, Albus and Teddy. Also we know that Victoire was born on the anniversary of the battle of Hogwarts. This is my idea of the ages and houses. Some is speculation and guess work (like Percy waiting three years at least before having a 2nd child) and some of it just personal preference

(As of summer 2018)
No first years

2nd year: Ravenclaw- Slytherin- Albus Potter Ravenclaw- Gryffindor- Rose Weasley, Scorpius Malfoy Hufflepuff-

3rd year: Ravenclaw- Molly Weasley Slytherin- Gryffindor- Roxanne Weasley Hufflepuff-

4th year: Ravenclaw- Slytherin- Gryffindor- Fred Weasley Hufflepuff-

5th year: Ravenclaw- Slytherin- Lysander Scamander Gryffindor- James Potter, Louis Weasley Hufflepuff- Lorcan Scamander

6th year: Ravenclaw- Slytherin- Gryffindor- Dominique Weasley Hufflepuff-

7th year: Ravenclaw- Lucy Weasley Gryffindor- Slytherin- Hufflepuff-

Graduated: Ravenclaw- Gryffindor- Slytherin- Hufflepuff- Victoire Weasley, Teddy Lupin

The summer after Albus' first year at Hogwarts was when everything began to change. It shouldn't have been a surprise, really. It was odd for peace to have lasted as long as it had, and though Great Britain had been mostly trouble free since the fall of Voldemort, the rest of the world had faced many issues, some minor, others not so much.

Life after Voldemort and Hogwarts had started off rocky for the trio. Hermione and Ron officially became a couple, which proved interesting given that Hermione had returned to Hogwarts to have her seventh year and take her NEWTs. Harry and Ron hadn't bothered with the schoolwork, and had simply taken the exams separately, Ron barely passing by the skin of his teeth. Ron visited Hermione when he could, but visits became more and more difficult, as both he and Harry had started new jobs at the Ministry. Harry and Ron quickly found that answering to bosses who had preconceptions about who they were and what they were capable of, was much different than answering to a teacher.

Once Hermione had finished her 7th year (and passed her NEWTs with flying colors), it became easier for her and Ron to carry on with a proper relationship. This often brought more trouble and awkward situations than had ever arose when the two had just been dancing around the issue. Ron would on occasion invite Harry over on a night that was supposed to be just him and Hermione, which always resulted in uncomfortable dinners which Harry would try to leave early from. Hermione made this difficult, because even if she was mad at Ron for forgetting a date night, she wouldn't let Harry leave without being a proper friend and host.

Harry did his best despite Ron's blundering to give his best friends the space they needed; after all, he was having his own trouble finding time to spend with Ginny. Ginny had finished up her schooling alongside Hermione and Luna, which gave the three girls an opportunity to become closer friends. After she finished school, Ginny had joined the Holyhead Harpies, a passion that took up nearly all her time. Harry had been thrilled for her, but it had left them with little opportunities to have alone time.

Little, but not none, as Harry and Ginny found the time for Ginny to end up pregnant, with a son. Ginny retired from Quidditch at that point, to become a reporter for the Daily Prophet, though it was Quidditch she continued to take interest in. They beat Hermione and Ron to the punch, as Ginny's older brother did not have his daughter Rose until three years later, when Albus was also born. More children came along, Hugo and Lily only being a year apart. If the trio's school years had been a slow march of fear, studying, and hormones, their married adult lives was a fast whirlwind of quidditch games at home, letters to Hogwarts, busy work days, and frequent trips to the school to attend a match, visit with Neville, or talk to Dumbledore's portrait.

And so the years seemed to fly by, more or less peaceful, until a month after Albus returned home from first year.