G'Day mate, best advantage you have here is that you have a complete car, this will make everything a shitload easier.
Wiring:
When doing this conversion, you use EVERYTHING from the EL, you will need to extend the headlight and taillight plugs so a soldering iron and electrical tape will come in handy.
Fitment:
The physical dash itself will sit in place without an issue, you will need a drill to remove the spot welds for the two side mounting brackets from the EL to put in place on the ED, make sure you line them up properly, using self tappers to hold the brackets in is a good temporary measure till you get them 100% and have a welder handy. You will need to use the steering rack and column out of the EL too.
To fit the seats and center console in, you will need to use your drill again and remove a spot welded floorsection out of the EL and to remove the old one out of the ED, along with the bracket for the EA-ED center console. When you have them both removed put the EL one inside the ED and hold it down with self tappers for accurate measurement and till they can be welded. One issue(Not major) that there is for this conversion is the different front threads for the seats, an advantage you have being an ED is that there are a few body similarities to the EF, the different hole is already there but a thread will need to be welded on for it to be any use.
Here is the floorsection from when I did mine:
Old:

New:

Mirrors:
The physical mirrors themselves will bolt straight in from memory, and if you are using all the wiring from the EL you will be fine.
Thermos:
Once again if you use the complete wiring out of an EL it's all plug in
Airbags:
Whilst they can be fitted up very easily I'd advise against it personally, your talking about a system designed for a completely different model, it's a basic system but it's personal preference, if you mount up all the sensors in the right place you wont have any issues. I didn't fit mine up for the reasons mentioned.
ABS:
The brake booster will bolt in without any dramas, but to fit up ABS you will need to use all of your brake lines from the EL and use an EL Diff, front brakes which you may want to consider a K Frame swap and take advantage of all the EL equipment. The ABS Unit will need to have holes drilled in to mount up. But if you use an EL Diff you will want to get the handbrake mounts off the EL and drill a hole in the floor, with the EL Floorsection in and the other associated equipment you can take advantage of the Floor mounted handbrake.
If anyone has picked any mistakes in this please let me know, iv'e gone all by memory.
Hope that is of some help mate,
Kyle

'95 DFII LTD - The Daily
302 Windsor, AU XR8 MAF, Exhaust, Sunroof, Slammed on Pedders, DL LTD Rims, FBT Steering Wheel, EL XR8 3.45LSD
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'13 Chrysler 300 SRT8Phantom Black, Black Chrome Group, Radar Red Leather, Dual Panoramic Sunroof, Mopar CAI. Mopar Front Strut Brace