Why did you change Shiina's name to Sheena? Shiina sounds more convenient and is also a meaningful word in Japanese, while Sheena has no meaning at all
We changed the names to follow the official spellings that was introduced by the author.
Here's from the bonus leaflet that came with volume 1, with everyone's name written in English. It's shown that the author has decided on these spellings very early on. https://cdn.discordapp.com/attachments/973311590550097953/998107750355709992/IMG_7339.jpg
And, as mentioned above, the official site that was made around volume 4 also have the spellings written this way: https://kimishinu.com/
There were some goods for KimiShinu as well, which uses this spelling: https://cospa.co.jp/detail/id/00000110068
To be honest, I felt like the original spellings were chosen because, as you said, it's the way you would romanize their names, as the original scanlators did not have access to these resources. Once we have the official spelling, I had a discussion with the original translator, and we both agree that it's best to use official spelling going forward.
The decision to change the spelling wasn't made lightly, and I apologize if it made anyone feeling uneasy after seeing them.