I replied to your later query about the hotel. Do you have your great-aunt's obituary from the Washington Post?

She is listed as Lottie Singleton, age 34, died Providence Hospital under deaths reported in the September 18, 1928 edition of the Post.

The next day is her funeral notice under Lettie Singleton, age 34, daughter of John and Catherine, sister of Francis. Mass was held at St. Dominic's Church and she was buried in Mount Olivet.

I would contact the church - they do have a website. Most Catholic churches published a newsletter with articles about members - birth, christening, marriage, death, etc. So, there might be an article about Lottie/Lettie in the parish newspaper. You should ask about historical photographs from this time era.

If the church does not possess the records from the era you are interested in you should ask how to contact the archivist for the diocese.

You might also be able to obtain her christening record which would have her full name. I often see cases where o is mistaken for e due to the looping through the middle rather than the top. Lottie might be a nickname for Charlotte. Then again it could be her name was Leticia.

Mount Olivet might also be able to furnish you with additional information about the family plot.

I also suggest you examine the free Chronicling America newspaper collection hosted by the Library of Congress. You can search for articles about your Singleton relatives and download them as PDF files. It may be time consuming, but you might find a gem of an article. You might even find an article about the Raleigh Hotel.

Good luck.