Crutchfield's website is very helpful for identifying compatible speakers for front door and rear headliner. I checked a few dimensions of speakers they list as compatible and from the small sample I looked at, speakers under 2" mounting depth are OK in the doors, under 2-7/16" is OK in the rear headliner.
I guess measuring on the Jeep is best for an accurate maximum depth but I wanted to save time ordering parts without having to first remove what's in there and measure the cavities.
Crutchfield lists these as OK in both doors and headliner on my 2001.
Kicker 46CSC654 has a mounting depth of 1-11/16" (43mm)
Kicker 43DSC650 has a mounting depth of 1-13/16" (46mm)
Kenwood KFC-1696PS has a mounting depth of 1-15/16" (49mm)
Crutchfield lists these as unsuitable for front doors, but OK for rear headliner.
JVC CS-DR601C has a mounting depth of 2-1/4" (57mm)
JL Audio C2-600 has a mounting depth of 2-7/16" (62mm)