Im with Badbenz,
No criticism here.. Sure their will be skepticism from time to time. But me, I’m a can-do, when there’s a will there’s a way kinda guy.. You have a desire and a vision - make it so!!
As for the tail light panel, I also agree to keep it 68. Since you are “merging the two,” I would share the uniqueness of each trying not to go too far in one direction. But again, your vision so whatever direction I’m following. 👍
Widebody thoughts,, Me personally, VERY FEW cars especialy classic Mustangs, in my opinion look right when flared or have widebody “add-ons..” Some of it is the execution and part is due to just going too far from the basic/classic lines of the car. I love the look of fat/wide tires but I also prefer if you want wide you go into the car not out from it. More difficult to do but it keeps it clean and original vs race inspired (fast and furious) looking. As my wife would comment: “it is more timeless, not trendy..”
I actually “modified” all four corners on my 65 (well, my vision but someone else executed it 😜). All by stretching/gently shaping the actual fender/quarters. Extremely subtle, maybe an inch in the rear and 1/2 inch up front. Kind of a coke bottle look vs flare. It just flows but in a way many would not even notice. Kind of like you, I took my 65 and added in a little 67/68 roundness where mine was flat. It’s the subtle changes/customizations that do it for me. Again, just an opinion not criticism. And I would fully agree - “who cares what the cat down the street thinks!”
Mod on!