Simplicity of the approach tau /. list and b /. list makes it quite natural to exploit. Nevertheless one can take into account another approach which can appear to be more efficient for long lists:

listtau = Last @@@ First @ Transpose @ list
listb = Last @@@ Last @ Transpose @ list

{32.8775, 24.4891, 12.6688, 4.84722, 0.134423, 0.103983, 0.0610192}
{0.299216, 0.277134, 0.356032, 0.30632, 0.965791, 0.587649, 0.999985}

Simplicity of the approach tau /. list and b /. list makes it quite natural to exploit. Nevertheless one can take into account another approach which can appear to be more efficient for long lists:

listtau = Last @@@ First @ Transpose @ list
listb = Last @@@ Last @ Transpose @ list

{32.8775, 24.4891, 12.6688, 4.84722, 0.134423, 0.103983, 0.0610192}
{0.299216, 0.277134, 0.356032, 0.30632, 0.965791, 0.587649, 0.999985}

It might be reasonable to consider also:

list[[All, 1, 2]]
list[[All, 2, 2]]