This seems a bit farfetched, but I looked though a few of the OP's historical connect walls and determined they are pretty liberal with red herrings, extra "unused matches", and stretching the idea of groups, so I am considering this at least within the realm of possibility. The key here is to note OP likes to make "at least four" words ...
My answer is D as well but I got to it slightly different way.
From right to left number of small, quarter, squares increases by 1 every step and colours get negated every step. So it looks like that (w for white and k for black background):
'squares': (?) 4 - 3 - 2 - 1 - 0
'background': K - W - K - W - K
So there are four squares on black background, ...
I came up with this pattern, which probably is not the desired answer but it's worth sharing anyway.
From Rand al'Thor's answer:
Now I noticed that if you order the countries by their given number:
So with this logic we can answer the first question with:
The answer to the second question would be:
Answer to the Third question:
So the valid word is:
I understand the meaning of the hints:
My guess is that the puzzle involves
Supporting this is the fact that
But I'm not sure what to do for the numbers with more than one digit: for example,
On the other hand,
At least I can partially answer the third question:
And the first question:
For the second question, I'm mostly ...
Very Partial Answer
I think I've got the gist of what's going on so maybe if I post what I have so far, it may inspire somebody else.
I have no idea about the street names on the map
Song Ideas (credit to MacGyver88 for figuring out the idea behind this)
Solving the rest
Bonjour Véronique and welcome to Puzzling Stack Exchange. Here is what I found so far:
For puzzle A, a possible answer is:
For puzzle B, a possible answer is:
For Puzzle C, a possible answer is:
For puzzle D I would say:
For Puzzle E, a possible answer is:
For the first picture, find the ones which have X, O, and Square. They must be either in same column or in the same row. In each row, look inside and check how many X, O, and Square is in a row or column. For the first row, there are only 2 X, O, and Square in a row and 1 as a column. We can now eliminate 1st, 4th, and 5th options.
Now search for 0, Square, ...