As a couple people have said, the photos make a solid ID pretty difficult.
But given that you have 4 RFAs in the tank, baby RFAs is a serious possibility. IMHO the tentacles and oral disks do look enough like some of my RFAs to say it's possible.
How did they get 15 inches away from the potential parents... they floated. When mom spits them out into the water column they are very tiny and have rather neutral buoyancy. So they float around some. Mine end up all over the tank, but I have crazy random flow in my tank. Another place to look is under the disk of the 4 potential parents. Feed them and see if there are any more babies under them when they fold up to capture the food. It's possible the current in your tank carried these all to one place.
How colorful are the 4 RFAs you have? Some have great color and some have very little color other than off white, tan, brown and green (and maybe some black striping). If you have 4 colorful ones, then these babies should have pretty colorful oral disks under blue lights. If the big ones are colorful and the potential babies aren't colorful, they may not be babies at all. But something else. Until I get to see better photos, I give them at 60:40 chance in favor of being babies. But that's just my uneducated, but experienced guess based on pretty poor photos.
Here is what some of mine look like. You can see 5 or 6 babies if you look around.
Here are a bunch of babies on an old coral skeleton. Click on the link and it will take you to my Flickr account full of anemone photos and some look kind of like yours.
https://flic.kr/p/Lj71w7
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