Recovering permanently deleted iCloud photos with exclamation marks

I deleted some photos on my current phone a while back, and I recently discovered my two old iPhones. I want to recover the old photos on both phones and have them on my current iphone. The problem is I want to retrieve the photos, but they have an exclamation mark on the photos and require me to connect to the internet to download the photos. I'm scared that once I connect to the wifi, the photos will no longer be on my phone and It will sync with the current iphone photos in my new phone, essentially deleting the photos I no longer have and keeping the ones I do. Does anyone have any ideas on how I can recover them?

[Re-Titled by Moderator]

Original Title: Permanently deleted iCloud photos