I can speak to one or two of these items.
The early track rods, also used on Mark V saloon, went through some development stages.
Here is my experience from 2008.
Note I did not ream out the track rod end forgings, I filed down the replacement parts to fit.
Your wiper motor mounting is the same as my Apr '50 Mark V and Nov '51 XK120.
I made new rubber discs and glued them on with JB Weld.
The fuel tank construction sounds like my '38 SS, about 25 pieces all soldered together, including the sender unit well. This was a new design for '38 that was not very well planned for high production. They were having all sorts of other problems with body parts at the time, and must have left the fuel tank design until last. What they saved on tooling costs they spent on labor.
Contrast the Mark V, planned for high production, and tooling prepared to stamp them out cheap and fast.
