Oh my goodness,
LynnaePB! Thank you so much for all of your information! AND your pictures! They are MOST helpful in trying to compare to what I've got. I've seen some of your posts in the "Silkies of Other Colors" thread! I tried to read as much through there to guess at colors before I started guessing what mine were.
So to answer your questions...
The lighter chocolate girl DOES have a stripe down her back. I doubt you can see her but she's right next to the black one on top. It's slightly darker than her somewhat dun coloring (*I had a Serama hatch out that same color and she's feathered into a lemon blue):
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That is also my very first Serama chick, bred here on my little backyard "farm", in the photo (*she looks just like her mom, who was born with that same color stripe and dot on the head and wound up becoming a silkied cuckoo so...big hopes! She wasn't fully dried yet but she was the only one left in the (VERY humid) incubator and was SCREAMING her head off being all alone so I popped her in a little early. I've got them in a brooder cage with a cardboard box in it and a heat bulb right next to my bed so I can always keep an eye on them. My husband thinks I'm crazy

)
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Just for reference, this is what her suspected mom looked like when she was a chick; same color stripe and dot on the head! It was just a day or so after this we discovered that she was a Silkied Serama!
The other little brown one, definitely does have the little stripes around the eyes and from above it does seem like there is a darker stripe down her back. I imagine she'll look somewhat like your own up there who had similar markings, without the stripes. And you can kinda see the stripe on tbe lighter brown one here, too.
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That's the darker brown one top left and the lighter one's head at the bottom (please excuse the errant flap of cardboard

)
The little gold partridges are the first I've hatched out with stripes. The silver partridge I have above came out looking very similar to the color he is now but no stripes and is also starting to display some red leakage so I guess he's likely a torti as well! As for the other girl, Hershey, she seems like she's going to color out into something similar (or just like) those Red Pyle ones.
Regarding your assessments of the blacks, I think we have ONE that will be full black; he is noticably darker than the other two and has no little feather tips that are silver or gold or blonde like my girl Hershey up there did. We've been calling the little black one, Vanta Black, since he's just SO dark!
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That's Vanta on the bottom there, sucking up all the light around him

And again, the darker brown one above him.
The other two, I also suspect one may be blue or gray. When Nickels (below) first hatched out his feathers were a noticeable silver/blue color and then he fluffed up and now all we can see are the littlest lighter colored tips. And the other one has a small gray patch under his chin/beak. I can't find a more up close pics of him so I'll be sure to get some of them all from different angles later today. But maybe they both will be gray or blue? I know they're two different colors, I am just so new to this that I'm not quite sure WHAT those differences are...but I'm very willing and able to learn!
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This is the Nickels. You can kind of see the light silvery tips to his feathers. Which is almost exactly what Hershey looked like at first only she had slightly blonde tips that turned into that deep red/brown she has.
But yes, you're very correct that this particular eBay seller has gotten me some chicks that didn't present with stripes and still came out partridge-looking. I believe he keeps a mixed color flock, otherwise, I probably wouldn't be having so much fun guessing what everyone will look like! He did say in the listing we could hatch out anything from partridge, black, white, buff, blue, or gray. I guess that's why I was so surprised to see that Hershey had the coloring she did! Honestly, I kinda like having the weirdo colors; I likely won't be trying to show anyone and personally, I like having the unique and interesting mixes. From your incredible mix of colors and patterns, it would seem that you do, too!
Your Silkies are all absolutely beautiful

And it's very, very clear to me that I must begin reading up on Silkie genetics before any of these guys get to breeding age. I have one black bearded silkie hen (named Henrietta) who I'd gotten to be the broody mom for my Seramas but then the older she got, the more beautiful she became and I was convinced I needed to provide her some friends. My little Serama cockerel, Rusty, has tried and tried and tried to mount her only for her to chase him around for a good five minutes until he relents for another few days

She's about 5 months ahead of these guys (so just laid her first egg) but I definitely notice she's warming up to my silver tortoiseshell partridge up there.
I also agree fully with what you wrote about the silver based white silkie
jnms posted above; he's absolutely beautiful! I believe my little white guy was buff based as we could not determine at first whether he was white or buff. But man, I'd love to get some little silver based white like that!
Thank you again to you both! You've been incredibly helpful and kind and I truly appreciate the feedback! I went into this whole chicken thing intent on breeding Seramas and now I find myself with a split flock of Silkies and Seramas, heh. At least they get along well!
I have to take some more individual pics of the babies today for my breeding partner/BCF (*best chicken friend

) so I'm gonna try to get some pics in natural light today and I will post them here once I've got them. Maybe we can get some better looks at everyone. She's trying to make some guesses at their genetics and just ordered this gigantic book on chicken genetics so we'll see what happens. I need to share the "Silkies of Other Colors" thread with her so she can see what some of you resident experts have already had to say
Truly, I'd be lost without this website!