To determine whether a line-up consisting of 6 universal candidates is appropriate, we need to carefully analyze the definitions provided in the problem:

1. Appropriate Line-up: This is a selection of 6 players out of 100 candidates that the coach deems capable of forming the team.

2. Perspective Set: A set of 5 candidates is considered perspective if adding one more candidate results in an appropriate line-up.

3. Universal Candidate: A player is universal if they can complete every perspective set of 5 candidates (that does not include them) to form an appropriate line-up.

Given these definitions, let's explore the reasoning:

- Suppose we have a line-up composed exclusively of 6 universal candidates, denoted by $C_1, C_2, \ldots, C_6$.

- Consider any subset of 5 candidates from this line-up, say $\{C_1, C_2, C_3, C_4, C_5\}$. Because all these candidates are universal, adding the sixth candidate $C_6$ to this subset must yield an appropriate line-up. This follows directly from the definition of a universal candidate, which can complete any perspective set into an appropriate line-up.

- This reasoning holds for any choice of the 5 candidates from the 6 universal candidates, repeatedly reinforcing that adding the remaining (sixth) universal candidate results in an appropriate line-up.

Therefore, the configuration of the 6 universal candidates inherently satisfies the conditions for forming an appropriate line-up:

$$\boxed{\text{Yes}}$$