General

DF is probably the best one to put in. You should put 5 ASAP unless you want some quick damage boosts, then go for total damage. Crit damage is second most important at endgame, but if you aren't hitting high or have high crit %, then put into total damage and boss damage second. Next, max crit damage and ignore def. Put final skills into status resist but it's not that important. Ignore Def is also lower on the priority list due to kanna buffs.

1. DF
2. Total Damage/Boss - Level up evenly
3. Crit %, Min Crit Damage, Max Crit Damage (aim for 100% crit, will need crit inner for this)
4. Ignore Def
5. Status Resist

You can put each skill to 5 if your eventual goal is to level up more.

^ What @loxiona said for the most part.

Personally, i didnt put any into status resist/power stance. For most of the high-tier bosses these stats are pretty much useless; and for the bosses where status resist matters, your haku's foxfire is sufficient. Power stance you have a base of 80% with haku's buff - which is usually enough for bosses with knockback.

Basically, the essentials are: Mana, Crit Rate, PDR (max these according to necessity) Then aim for min/max crit (probably up to 7? i think that was were mathematically it was most cost efficient, dont quote me on that), if you arent capping yet. The rest of the points you can put into whatever.

This is just my opinion though3

Mana and crit stats should be maxed definately, since kannas really lack in crits. Damage and Boss Damage also good, i'd evenly build these up next.

extra points you have could go into abnormal status resist, power stance, or ignore def if you're lacking in that