n1480
 

Is a legal target for 's effect, or does "name:tsunade" not meet the requirements?

from the rulebook:

Name: X - Ninja and Client cards may have a “Name: X” Characteristic. This card is considered to have both its own name and the X name designated by the “Name: X”. This second name is taken into account for name restrictions in regard to deployment and Jutsu requirements.

note that it doesn't say "this ninja", it's saying that the card itself is considered to have both names.

Yes, n1480's effect can put in play n1259.