I have a 4-party consisting of:

Monk Felpur
Ninja Gnome
Priest Mook
Samurai Hobbit (formerly mage for 12 levs)

They are all about lev 16 now.

The ninja does not have double attacks yet but all others do. She has the best speed and dexterity (both over 90) plus staff, close combat and dual weapons all above 50. Her weapon (or weapons when using 2) is +2 init. Is there some longer learning curve for ninjas?

How are you wielding two staves??? (are you playing a mod that has an either-handed staff?)

If you're wielding a staff and something else, your ratings go down according to your skill in the other weapon.
If you are carrying too much your init goes way down.
Weapons have a variety of their own initiative effects.
Click on the equipment icon near your attributes to change to the weapons stats page and change your weapons around so you can see what's the best thing to give the Ninja.

Using 2 kama staves (Flamestyrke mod).

My guess is the problem was with initiative. Finaly got the second attack. I had gone to 2 attacks with a single stave, but I guess I reached the magic number for 2 weapons on next lev.

In this mod I also got a *light* *sword* drop in the Northern dungeon.

yah, heh, i didn't think of it before, but isn't your Ninja a level behind everyone else by now? That'd make a difference, duh.