1) If I use 'when' instead of 'like' (in "And you can feel the resentment like paint...), what differences will arise?
Doesn't work at all for several reasons, one of which: With "when" you'd have to say "fumes are swirling," an entirely different meaning
2) I think, here, 'splinters' means 'break'. Am I right?
3) Blue is shouting to Yellow? What does it mean?
The various rooms are painted by teams. The blue team is shouting to the yellow one
4) What is meant with "about having the most
Each team thinks its job is more nearly perfect
5) What is meant with 'skirting-board race'?
Dunno Ahmed; might involve a ladder; maybe Lay or Con or S. can further help you