Well, if nobody else is gonna answer.....
It's your car; you do not have to worry about anybody else says about what you do to it. Besides, nothing you've posted is an irreversable mod. Having said that I'll also say that, should you ever decide to let the car go, having the original parts (that your replaced in your upgrades)on hand could result in you collecting a major chunk of change over what the car would be "worth" in its modded state.
To that end, may I also suggest that you look into the user reviews on the Borgerson integrated power steering box; rather than the old 'assist ram' original system. Less potential for cylinder leaks, P/S hoses not spaghetti'd around between the headers (should you get headers) and the speed bumps and debris on the road....
Bolts right in to the existing holes. The downside is that the early stangs had a solid, fixed shaft that went all the way from the steering wheel to inside the box - that's not going to work without major irreverable mods to the column and shaft. Just go with a '68 column from a junkyard or an aftermarket like an Ididit and mod away.... again, keep the old stuff intact just in case you someday want/need maximum cash for the car.