#2,4,5,6: used to #3: would #1: both “used to” is used to establish past time frame in situations where it is otherwise not established. “would” works best where a past time frame is already established. In #1, present and past time frames are both established.

Both forms can be used to describe habitual actions in the past, usually not the recent past. Using ‘would’ is a more formal way of writing. All the sentences are correct with ‘used to’. 1, 2, 3, 4 and 6 could use ‘would’ : 2, 4 and 6 should be preceded by a sentence that provides context, without which they are incomplete. In 5 ‘would like going . . ‘ sounds unnatural; ‘would go to formal dances’ is better,

For me the last one has both answers, just this one.😬