you should drop your stealth to 85....at 85 you never fail and you can use the extra points towards ninja.
if you cast the spell animal form and select dog form(not wolf form) you will regen hitpoints and the higher your ninja the faster you regen and you can use chiv and gheal pots for extra healing.
Yes and no.
My ninja archer has 75 stealth (75 is all ya need) and 80 hiding.
My ninja swordsman has 100 hide/120 stealth (actually 110 and wears the +10robe) because any lower makes deathstrike do less damage.
On an archer that is of course not a factor, so less is fine...but if you plan on using DS and want it to do more damage you need 120/100 (and at very least human form tracking to go with it...more would be better)
As for the chiv, since I cure with pots, and avoid using Divine Fury (red pots ftw) I felt no reason to have more than 50 chiv...which is plenty to cast close woulds, and remove curse. This is for pvp of course. More would be nice...105 for holy lights would be great since I run 4/6 casting...but there is just no room for it on my template.
This is what my temp looks like
120 swords
120 ninja
120 bushido (confidence+nerve strike+lightning strike)
120 stealth
100 hiding
100 tactics
50 chivalry
With human form tracking (20 skill) I can do a max of around 52 on a deathstrike, and if I don't track its 42 or thereabouts. With higher tracking you can do a lot more.
4/6 casting, 50% ep, max lmc, 10 mana regen, 45 hci/65 dci, corpse proof suit (75+ fire/poison)
As for the original question, I of course heal with chiv, pots, and confidence. If this were an archer template (deathstrike sux on archers) I would not have the bush, chiv, or as high hiding/stealth and would go with anat/heal...