Short answers, pulled from the story.
The transition occurred on the 29th of March 1809 when four Estates gathered at the Diet of Porvoo and pledged allegiance to Tsar Alexander I. The Treaty of Fredrikshamn signed on the 17th of September 1809 finalized this shift.
Count Gustaf Mauritz Armfelt returned to Finland in 1812 to secure the grand duchy as a state with greater autonomy. He acquired so-called Old Finland that Russia had annexed from Sweden decades prior.
The publication of The Kalevala in 1835 peaked a reading craze known as Lesewut. This Finnish epic influenced the nation massively and strengthened nationalism and unity.
General Nikolay Bobrikov served as Governor-General from 1898 until his death in 1904. Eugen Schauman assassinated Bobrikov in Helsinki on the 16th of June 1904.
The population reached 2,380,000 by 1890 according to historical statistics. The population reached 2,943,000 by 1910 before final independence.