An object is used to get at a branded project launched in 2016 that shares its colloquial name with something first won in 1893. What links all three objects with a famous fictional military know-it-all?

I think i've worked out a few parts of this but I'm still missing something.

The Stanley Cup is the 1893 first won object.
The 2016 product launch "Stanley Cup" it references is a mug released by Stanley, called the Quencher Tumbler.

What I'm not sure of is the third object, or the famous fictional military know-it-all.

If you mean a branded "product," you're probably cluing to the Stanley cup. The company Stanley (which has been making drinkware almost as long as hockey's trophy has been around) first sold the Quencher in 2016, a big steel vessel with a plastic lid and a straw. In 2020 it went viral on TikTok (and was dubbed the "Stanley cup"); some limited edition Quenchers have sold for over $500.

"Stanley Cup" happens to be the name of the National Hockey League's top prize, first awarded in 1893 to the Montreal Hockey Club. That trophy is named for the British politician Lord Stanley of Preston. By tradition, the team that wins the Stanley Cup is expected to drink champagne from its bowl.

If "An object is used to get at..." clues to a third object, you might be speaking of a Stanley knife, a.k.a. a box cutter. Stanley knives are made by Stanley Black & Decker, no relation to the Quencher-mongers.

As for the know-it-all, you're probably thinking of Major-General Stanley, the very model of a modern major-general.

https://www.youtube.com/watch?v=hlTisI_HSgw