My current YJ had a seized door on the driver side. Everything inside was stripped and seized. It took a boatload of hammering and prying to get it to open, and she's SEIZED open now.
It's likely your best bet to pay a garage a half hour or hours labour to get the door open and latch free'd up, if it's possible. You've already got the panel off so any decent technician should have it open in about a half hour... more if you want him to free it up.
'91 Frankenheep YJ. 4.0, 4" BDS, Richmond 8.8, Titan 12k, 35" KM2's, rust.
'88 YJ, 4.2/4.0 head, +4½" & shackles, BFG 33's (sold)