First Ladies that would've died in office had they completed a second term

[Plankton5165]

Also, who would the new first ladies be?

Jane Harrison (d. 1847, second term would expire 1849)
Peggy Taylor (d. 1852, second term would expire 1857)
Abigail Fillmore (d. 1853, second term would expire 1857)
Florence Harding (d. 1924, second term would expire 1929)
Ivana Trump (had she still been married to Trump; d. 2022, second term would expire 2025)

As you might or not notice, every president that died in office of natural causes and didn't serve more than two terms has a first lady on the list.

[Plankton5165]

Since no one has answered the question, I figured I'd give my answers:
Harrison:
Anna Harrison (1775-1864) - I mean why not? She was still alive at the time of Jane's death and probably wasn't going to wait until that long to recover. Anna never served first lady duties. I think that's why Jane is listed.
Taylor:
Mary Elizabeth Bliss (1824-1909) - Already temporary took her mother's place.
Fillmore:
Mary Abigail Fillmore (1832-1854) - Same with Mary Elizabeth Bliss, however she died before the second term could be completed as well. That means I would state another first lady.
Maranda Fillmore (1810-1875) - One of Millard's sisters. Millard Powers didn't marry so I figured she would take the role. Could be wrong but not impossible. Millard didn't marry Caroline until 1858.
Harding:
Carolyn Harding Votaw (1875-1951) - Sister of Warren Harding, who had no legitimate children.
Trump:
Ivanka Trump (1981-) - Trump's daughter as you most likely know of the six. Could also be Vanessa (Donald Jr.'s wife), I figured it would probably not be Tiffany because Donald had her with Marla, unless he were to divorce Marla and then marry Ivana again. IRL, Melania is pretty young for a first lady too anyway, I thought.