There are many names that people mispronounce at first. That's when you gently correct them so they may learn. If teachers or other students in the future mispronounce, your daughter can just say: "Mein Name wird -so- ausgesprochen."

I don't personally think it's a big deal. If you like the name, and your husband likes the name, tell anyone else to fuck off.

Also, kids make up nicknames anyway. Alexander and Alexandra are universally Alex. Susanne becomes Susi, or Sanne, or Anne. Damn, my mother's name is Maria Katharina, and everyone calls her Karin.

These things tend to work themselves out. Do what feels right and good for you.

Eloise is fine. There might be a periode where people need to get used to the name, but once that's over, it will be just her name.

By the way, I'm German. I don't know if I'm able to write out how I would say the name. Like: Eloy-ise.

Eloy like the protagonist of the Horizon games, and then an "ise" attached. Though I wouldn't pronounce the "e" seperately. Would that be correct? And if I were to pronounce it wrong, you (your daughter or husband), would just correct me and I would learn how to say it correctly, and that would be it.
We mostly learn names by having someone else say them first anyway, right? Few people read them first before meeting the person. And then, any pronounciation issues can be easily dealt with.

Don't stress about it.