You're forgetting Tsubasa and Konatsu.  BTW, would you consider
Tarou a second string character (never mind what Tarou would 
think), or would Rouge be more apt for this?

 Not very familer with Tarou, from what I've heard, he is a big-
timer

 >  Other suggestions from UY include:

Onsen Mark
Tobimaru
Ryoko Mendou
Sugar, Ginger, & Pepper

 But Ryoko does have all those ninja she can call on(Even an army) So 
that bumps her up to 'Valuable'

Shinobu

Second Stringer. Plus this is more for the obvious losers