The song is "story of tonight" (workshop) from Hamilton
(The video above is not mine and is only being used for audio)
"I may not live to see our gory-"
"I may not live to see out gory!"
"But I've seen wonders great and small~"
"I've seen wonders great and small ~"
"But if the tom cat can get married-"
"If Alexander can get married~"
That's all I have now, but it'll probably be done tomorrow x3