We sold our old house after we had bought a new one. (Correct tense)
The road was blocked because a tree had fallen on it. (Change "had been falling" to the simple past "fallen" because the action of the tree falling happened before the road was blocked.)
The street was icy in the morning as it had frozen all night. (Correct tense)
I was full of energy because I had had a big lunch. (Change "had been having" to the past perfect "had had" because you're talking about a single big lunch you ate before feeling full.)
Had you ever slept in a tent before your holiday in Italy? (Correct tense)