Huh, I always thought that poison/ignition applied at beginning of round. There is no practical difference most of the time, but might affect interaction between ignite and begin-of-round-self-heal ninjas. It also might affect death-by-DoT oorochi/hidan rez timing. Can someone check and verify?

Sleep can be awaken by an attack, I'm not sure if it last shorter than the other stuns thou if not awakened by attacks.
Stun in general have an odd duration. Specifically, IF the target have NOT performed his normal attack YET, then it will end at end of round.
Otherwise, it will end it the end of NEXT round. This means if you are using fire main, it's best to use his stun on a char in the middle of turn as opposed to start(unless you need to interrupt an enemy mystery with it)
Fairly sure that paralysis works the same way, thou usually those are applied at beginning of turn so the enemy can't do a mystery chase chain, so the extra round thing is rarely seen.
Furthermore, all stuns also prevent chase skills from being used, this was not mentioned.

It is worthy to note that acupuncture carries an interrupt within it. This is important when the acupuncture itself is reflected or the target is immune to status effect, the skill will be interrupted nevertheless. I have not, however, tested if you have Hidan, who is immune to interrupt, on a team with Kurenai or fire main, who can reflect the status and what happens when Hidan get acupuncture. Because I know that acupuncture that *S will stop his skill, as he is only immune to interrupt, but if the acupuncture doesn't *, I don't know if his skill will be stopped. (note not *ing is DIFFERENT than *ing then get removed)

on a side note, chaos on a ninja that doesn't have a regular attack can be quite interesting....

For the record, I believe I've seen Sage Naruto under chaos w/o a clone up summon a clone.
It might be interesting to note that as far as I know, there is only one way to attack out of turn: if the ninja was resurrected after its turn