>>1467Albania's army was much smaller than Yugoslavia's and Romania's, and furthermore the defense doctrine of the country was based on the whole populace (i.e. civilians) being trained in basic armaments. Combined with the mountainous geography the bunkers were seen as logical.
As for the international situation, the bunker campaign got underway when the Soviets invaded Czechoslovakia. Greece had also proclaimed itself in a "state of war" with Albania all the way until 1987. So there were fears about the Warsaw Treaty and NATO countries.
Albania continued making rapid economic and cultural progress throughout the 70s, the bunkers didn't impoverish the country.
As for your last question, Mao in 1956 and Mao in 1960 had two different positions. The Mao in 1956 was supportive of Khrushchev, the Mao in 1960 wasn't. Furthermore Mao's critical remarks on Stalin (such as in "On the Ten Major Relationships") weren't officially published until the 70s.
The Albanians always had reservations about what the Chinese were doing from 1956 onwards, just as they had reservations about what the Soviet revisionists were doing from 1953 onwards, but they initially felt that the Chinese were simply mistaken on a few issues and that they themselves (as in, the Albanians) didn't know everything and weren't in a position to assume the worst.
As Hoxha noted, the CPC was very much a "closed" party when it came to relations with other parties. Even in state-to-sate relations the Chinese side was very tight-lipped towards its ostensible European ally. This is made clear from Hoxha's "Reflections on China."
But it is worth noting that even after 1978, Hoxha never felt that Albania was wrong to side with China against the USSR in the initial period. In his book "The Khrushchevites" (published in 1980) he said that the Soviet revisionists behaved in a most un-Marxist way towards the Chinese and that the Chinese at the time seemed to maintain basically correct positions on the important issues (Stalin, peaceful coexistence, building socialism, etc.)