If Win 10 was one of the options I could DL when creating the USB installer, I would have, but Win 7 was the only OS listed. If you're suggesting that I buy a copy of Windows 10 & install, just because I'm a nice guy, I think not. They're getting a free computer as it is!
If the Win 7 product code would activate Win 10, then I would do it.
BTW, that USB installer didn't work as I had hoped for - I still had to DL all the drivers...
And FWIW, I am running Win 10, myself, so I don't have anything against it!
I don't know of any ISO that has the Dell drivers "built in".