Here is my take on these questions.
Q. 4 c is the only one with a right angle, a is the only one with the square touching the tip of a triangle. Why e?
Logic is to do with the sides (triangle and rectangle) touching.
Q.8 why b and not a? Is it because of the shading? Is it really that easy?
Hard one. Remember discussing this with DS few days ago. The only thing we found was that the outgoing lines kind of leave from the middle-ish of the circle.
Q.10 Why e? Its so different!
Another one we discussed. The shapes in the question have straight line vertices. That eliminates 'a' and 'c'. We have shapes similar to 'b' and 'd' in the question with different shade, so eliminated. That leaves with 'e'. This is a clear demotivating question.
Q.4 A = two crossed squares, but what does the second letter represent?
First letter is to do with the black dots and their alignment. A - vertical; B - horizontal; C - diagonal.
Second letter is to do with the number of crosses. U - 2; V - 3; T - 1; S - 0
Q.7 we just can't figure out any of the codes
Ignore the little outer square.
First letter is to do with the number white/blank squares. D - 2; F - 1; B - 3.
Second letter is for the pattern.
Q.8 B = black triangle, so the first letter is D, but what is the second letter?
Honestly no idea.
Q.3 it is going to have 4 little lines, but what other logic is there?
Few combined logics here.
1. The vertical lines shifts the position as we move down each row.
2. The little lines go 4, 3, 2, 1, 0
3. The black square moves down but diagonally in each row.
The above are my (and DS's) logics. There could be other logics to arrive at the same answers.