In NEON, have the three instructions( VCLS, VCLZ, VCNT), are they all count sign bit?

In NEON spec:

VCLS (Vector Count Leading Sign bits) counts the number of consecutive bits following the topmost bit, that are the same as the topmost bit, in each element in a vector, and places the results in a second vector.

VCLZ (Vector Count Leading Zeros) counts the number of consecutive zeros, starting from the top bit, in each element in a vector, and places the results in a second vector.

VCNT (Vector Count set bits) counts the number of bits that are one in each element in a vector, and places the results in a second vector.

I want ask:

1. If VCLS is must apply to signed number?

2. If VCLZ is must apply to unsigned number?

3. Whether VCNT can apply to signed number,  if it can so the sign bit is also count as one set bit?