The holes were cut for grease fitting access, no problem just not very neat.
Great, but when you mean no problem, is that no problem leaving them as is, or it would be no problem patching them?
I agree with the post above on the hood latch, if you need the electric fan, remove the latch completely and install hood pins.
Why is there an extra fan? Don't you suppose that was put in as a Band-Aid for some other deeper problem in regards to keeping the engine cool?
Those seats don't look stock to start with. Headrests that are more then just looks CAN"T be retro-fitted to an old seat. How about looking for a late model bench out of a small pick-up...Ranger..Toyota...Nissan...something like that? Bench seats are common in them and should be able to find something the right size. You'll have to get creative with mounts, but that shouldn't be a biggie.
I'm not at all opposed to putting in seats from an entirely different vehicle. Keeping the car stock is a minor priority. The goal is to get it near stock, like 70-80%, something along those lines, mostly so that it remains of the period for the most part, and generally is clean, punchy and fun to drive. When you say, though, that I might need to get creative with the mounts of a bench seat foreign to the car, are you meaning the cutting, repositioning and welding of the mounts on the bench seat? Having not even pulled the existing seats from the car, I really don't know what to physically expect in regards to bolt pattern, orientation and hardware.
Random question to anyone: will I need universal joint and/or deep well sockets (i.e. does working on a Ranchero present a lot of tight corners and spaces, or will regular socket make do? I'm still researching air compressors, impact wrenches, engine hoists and stands, floor jacks and jack stands, not to mention transmission jack, a piece of equipment I don't know whether I will be needing.