Learn English – What’s the meaning of “to dog his heels”

The idiom speak volumes (about something refers to communication without words, which is why, in your examples, a yard and a house can be said to speak.

If something speaks volumes, it makes an opinion, characteristic, or situation very clear without the use of words:
She said very little but her face spoke volumes.

(Cambridge)

See also the other definitions and examples given at The Free Dictionary.

Applying the idiom to written communication does not represent natural usage of the idiom.

It does not seem out of place regarding formality in the sentence you wrote. So, yes, the idiom can be used in a formal essay, including "writing to your college director to do some proposal to improve building's installations."

Dutch native speaker here, 'golden fingers' isn't an idiom here. Like you (Russian?) we do have 'golden hands' (see this article in Dutch); that phrase isn't used that often, but refers to King Midas' golden touch.

As @WeatherVane suggests in the comments, I'd use 'magic touch':

: a special power, influence, or skill that can be seen in the way something is done : an ability to produce good results in an impressive way

(source: Merriam-Webster)