I have four unidentified photos, all from this studio but with variations in the logo stamped on backs. Can anyone help me pinpoint dates for following?

1. 1st 3 lines centered on back:
Eggleston & Co., (italics and handwriting-styled font)
Photographers, (bold, Times New Roman-styled font)
Chardon, O. (same style as line 1, but font size smaller)

2. Same as #1, but lines 1 and 3 are same size font

3. Same text as above, but framed, with cherubs and old-style camera with tripod on top of frame.

4. Same text as above, but set in a scrolled frame.

At bottom of each card, on back, says "Negative Preserved."

Thank you for any help.