The Clauses ages... Best guesses?

GRANDSANTA: 136
MALCOLM: ~110
MS. CLAUS: 70s or 80s
STEVE: ~50
ARTHUR: 30s

So, it's obviously implied that the Clauses live longer than normal people. If it's Malcolm's 70th mission his in his late eighties early nineties AT LEAST.

It's stated Grandsanta is 136.

136-90 = 46. At the very latest Santa was born when Grandsanta was in his forties. It is more likely it was earlier due to this:

There is no implication that Ms. Claus has the gene of long life as she cannot be related to them (hopefully.) So she looks about 70 or 80. The wedding picture in the background of a scene she had darker hair, and it's a black and white photo, while Malcolm has his white beard. HE IS OBVIOUSLY OLDER THAN HER IN THAT PICTURE. There's also a colour photo on her nightstand of her young self in front of a 1950s sleigh-car-thing. So, around the 1950s they were married. That puts their marriage at a maximum of 60 years with a ten-year leeway. Malcolm HAD TO have been married later than his 30s due to the beard. A conservative estimate would place him in his 50s at that time. THEREFORE:

HE WAS BORN IN THE 1900s WHEN GRANDSANTA WAS AROUND 25 YEARS OLD.

MALCOLM IS ABOUT 110 YEARS OLD.

Steve, with grey hair, looks considerably older than Arthur. They had to have had Steve shortly after they were married. That would put him around 50 years old.

Arthur at the VERY LEAST has to be 35. Why? Because, if Ms. Claus is around 80 years old, the latest she could have a child is around age 45... Hypothetically, if she was born in 1931 (80 years old), the latest years she could bear a child would be around the 1970s... Putting Arthur between 30 and 40 years old.

Why so they live so long? I'm guessing it's because of blessed magic of their ancestor St. Nicolas or something...

I dunno, I'm overthinking this...

28 days, 6 hours, 42 minutes, 12 seconds. That is when the world... will end.