Re: If an electric guitar is acoustically louder, does this translate through pickups
There are several schools of thought on this one; perhaps they would best be called schools of opinion.
What's undeniable is that vibration transferred to the body & neck is lost to the string. This is basic physics.
But opinions differ widely as to how this translates in actual playing.
A string will sustain longer and have better treble response if there is minimal vibration transferred to the body and neck (because high frequencies carry less kinetic energy than lows and so are more easily damped). I think of this as "inherent" sustain. It's why back in the 70s people favored heavy brass hardware and very dense body materials like metal, heavy wood, and even stone.
Necks affect it too, that's why rigid necks have brighter tone with maple generally sounding brighter than mahogany, multi-piece laminated necks being brighter still, and metal necks being brightest of all.
However, not all of us prefer a bright sounding guitar with a very stiff neck. And in a guitar that's louder unplugged, the same easier transfer of energy between strings and instrument also goes the other way when amplified: ambient sound energy vibrating the guitar - especially the neck - can flow more easily back to the strings.
This is the magic of liveliness and you can feel a lively guitar take off at much lower volume than a stiff heavy one. I think of this as "live" sustain.
On another forum that's less welcoming than this one, I was basically dismissed for proposing this. Some tried to cite science which (they said) proves that very little energy can get from the strings to the neck or body.
However, anybody that's actually played a guitar knows that you can feel the body & neck vibrate when played. And science tells us that with very few exceptions, when energy transfer occurs it generally behaves the same way in both directions.
Another angle is that when sound is shared more freely between guitar and strings, the nature of the neck & body will exert more influence on the tone, because there's more energy bled away from the strings and the frequencies affected can vary from one piece of wood to another.
I used to try out a couple of dozen brand new Strats or Les Pauls side by side: same model, same year, same type of wood, same hardware & pickups. They weren't all exactly the same, and some were really quite different from each other.
Myself, I generally favor a more lively feel, even if it isn't as bright, even if it doesn't sustain as long when unplugged. I once had a broken Gibson headstock repaired and when the guitar came back it was brighter but had lost some of its lively feel. I've heard of players who actually prefer repaired headstocks because of the extra brightness, but for me liveliness is paramount. As nice as that Les Paul was, I sold it eventually.
Now, all of that being said - and as comforting as it would be to have a universal formula- none of it is a hard & fast rule. I've had heavy guitars that were still lively at volume, and some guitars that were pretty strong unplugged but didn't really sound great or come alive when amplified.
Generalities are just that, and some guitars will defy preconceptions. As others have said, it isn't wise to write a guitar off just because it doesn't fit a qualification like sounding loud unplugged.
They can surprise you.