No SD card in iPhones, but all the phones could use a single cloud service. I’m not a fan of Google anymore but using Google for images was an easy route to go, if there’s no issue with the images being in the cloud. All 3 phones could connect on WiFi, download Google Pictures app, and backup all the pictures to Google Pictures. Use 1 account and login to it on each phone. Those pics can be accessed from each new phone or pc anytime in the future. Also, you can set your phone to automatically backup new pictures taken straight to the Google images account. Set it and forget it and have all the images. Back when I used it, I opted for the FREE unlimited storage. As far as cell phone pics go, IMO, the quality is no different than the ‘Limited Full Size Image’ option.
Since you have a mixed bag of cell phone brands, a cloud based option maybe the simplest. With the iPhone, using iTunes on your PC is the smoothest process for getting the images. However, it can be a little buggy if it’s an older phone or synced to another pc in the past.
If I was in your position, I would:
Go the Google route. Upload all the images from each phone - no cords or cables required.
Get on the PC, search Google Photos
Login to the account you created to backup the images
Save any pictures you want from there to a hard drive if you want or just leave them in the cloud.
Sorry for the long post, but that seems like a good option to me. If you go that route and need help, let me know and I can streamline those steps some with better detail, but it’s not that bad. Hope this helps