Leapers is based in Michigan.
The Leapers UTG ACCU-SYNC Spring-Loaded AR15 Flip-Up Rear Sight mounts to Picatinny Rail but will not fit a Weaver Rail.
Yes, when the Leapers UTG ACCU-SYNC Spring-Loaded AR15 Flip-Up Rear Sight is folded down it is 1.21 inches long.
The F fixed front sights are slightly taller than standard which would require you to adjust the front sight post up or get a replacement taller front sight post.
Yes, the windage adjustment wheel provides tool free adjustment of the dual aperture sight.
I was unable to find the folded dimensions for the Leapers UTG ACCU-SYNC Spring-Loaded AR15 Flip-Up Rear Sight, but I would not suggest trying to fit it folded under the Sig Sauer Juliet 4 (as there are no dimensions offered for the space underneath the magnifier).
The Leapers UTG 3X Magnifier with Flip-to-side QD Mount sits at 1.80 inches high, and is a different size than the factory rear sight on the Chiappa Little Badger. It can definitely mount on the rail on the Chiappa Little Badger.
Yes, this will mount to a picatinny rail.
This should be a great fit. The length is 1.21 in, with a width of 1.41 in.
If the Daniel Defense fixed front sight is for a AR15 platform, as this Leapers UTG ACCU-SYNC Spring-Loaded AR15 Flip-Up Rear Sight is AR15 specific.