BL manga with MCs as parents/guardians

A young father brings his energetic twins to a public bathhouse, where he meets a kind man who offers to help out with the children.
•
• children are 14 years old and pre-primary school

Aoi is raising his deceased lover's child, and on his way home one day finds a dog. He attempts to find the dog's owner, but ends up stumbling upon an old building, home to many dogs and a mysterious man.
•
• child is in primary school

A handsome pilot is in need of a housekeeper, and luckily for him, his son finds someone perfect for the job.
(pp 9 - 110, 194 - 195)
•
• child is pre-primary school

A college student's sister drops her daughter off at his house, telling him to take care of her until she gets back. Finding out about his struggle, a classmate offers to help take care of the young girl.
(ch 5 - 6)
•
• child is 3 years old

Yagami, a single father, zones out on his way home, and doesn't notice the vehicle coming straight at him. He's pushed out of the way by a concerned bystander who breaks his arm in the process. The man, Okumura, asks that Yagami compensate him by being his slave for a month. Yagami and his young son move into Okumura's home, where Yagami begins his month of servitude.
(ch 4)
•
• child is in primary school

A college student is suddenly approached by a professor he's never met and is asked to babysit his son.
•
• child is 5 years old
• 9 year age gap

Yajima falls for his new neighbor, a single father with a baby who enjoys screaming his lungs out in the middle of the night.
•
• child is a baby

Tanihara takes his young daughter to the doctor, who is immediately infatuated. The doctor later approaches him and admits that Tanihara is his type, and luckily for him, Tanihara is up for trying something new.
•
• child is in primary school

Mizuki has a forbidden, unrequited love. Even worse, the object of his affection is his brother-in-law, Morito. But what are Morito's real feelings for his wife? Just who is it he really desires?
(ch 2)
• (initially)
• child starts as a baby

Shinnosuke becomes a live-in housekeeper for the Toura brothers who, so far, have driven out every housekeeper they've hired.
•
• children are 14 and 17 years old
• 5 year age gap