Beyond the points that Acedrummer_CLB exquisitely exposed, I think that in every occasion you could apply more than one effect under the same conditions and these effects come from different sources (powers, feats, whatever), you could apply them in the order you prefer.
I have found no reference to support this "rule": I simply decided that if there is no explicit ordering criterion, an arbitrary one could be used.
I think, however, that the effects of all four feats in the example should fall under the hit or miss phase (they all apply only on a successful hit only).
Under this hypothesis while the decision to exploit the Deft Hurler option takes place before the attack, its effects, Cruel Cut Style, Longhand Student and Criterion of Balic Practice effects could all take place in the hit or miss phase.
These four effect are not simultaneous, but could be applied in any order. A possible sequence of play could be:
- Before the attack: Deciding to use Deft Hurler
- As you attack: You compute attack and damage bonus and check if you hit you primary target.
- Hit or miss: You hit the Cleave target and deal damage as normal.
- You use the Longhand Student benefit, thus pushing the target one square (and isolating it from its allies).
- You use the Cruel Cut Style benefit to the now isolated target and deal it ongong Wisdom modifier damage.
- You use the Criterion of Balic Practice benefit and shift 1 (or 2) square(s); you are now in range for a ranged basic attack against the artillery monster.
- You use the Deft Hurler benefit to make a ranged basic attack against the artillery monster.
- After the attack: none.
I have found no reference to rules that prohibit the appliance of multiple "at-will attack modifier" effects. A more formal at-will attack modifier definition or keyword may be needed.
However, as the number of publish material grows, some at-will attacks could become far more powerful than many encouter attacks.
I'd house rule that no more than one "at-will attack modifier" feat could be applied on a single power utilization; and this decision must be made in the before the attack phase.
There are three issues here, I think: Keywords, the two different kinds of proficiency, and permission by omission.
But before I go into those, a word: As always there are explicit features/feats/enchantments which break the rules, and that's why we call D&D an "exception-based" system: it deals in rules which apply universally unless (until) exceptions are made, so there is no need to enumerate the possible exceptions. We simply assume the rule unless told otherwise in a particular instance.
Keywords
If a power has the weapon keyword, and only if the power has the weapon keyword, does a weapon enchantment (enhancement bonuses and other features) apply to that power. Ditto with the implement keyword and implement enchantments.
Proficiency and the Proficiency Bonus
"Proficiency" means that you've had training in the use of a weapon or implement, but mechanically it means totally different things whether you're talking about a weapon or an implement.
Weapon Proficiency and the Proficiency Bonus
Proficiency with a weapon means that you can add that weapon's "proficiency bonus" to attack rolls. Only weapons have proficiency bonuses, they only apply to powers with the weapon keyword, and they have nothing to do with whether enhancement bonuses can be applied (see below for that bit).
Implements, Enhancement Bonuses, and Permission by Omission
You need to be proficient with an implement in order to add its enhancement bonus to attacks and damage with implement powers. You do not need to be proficient with a weapon in order to add its enhancement bonus to attacks and damage with weapon powers, but you don't get its proficiency bonus to the attack roll. (In either case, you can only add the enhancement bonus of one item at a time to an attack unless you have a rules exception which says otherwise.)
I arrived at this conclusion because the magic implement rules say you need to be proficient for the enhancement bonus, but the magic weapon rules don't. Permission by omission is sloppy, but has solid precedent.
Best Answer
For Dancing Weapon: No, dancing occurs in her square. She provokes from enemies adjacent to her,they attack her.
For Greater Dancing Weapon: Yes and OAs are provoked from squares adjacent to the weapon
First, the power of Dancing Weapon:
The first line we care about is: "You can deliver basic attacks and attack powers through the dancing weapon as if you were holding it yourself (including all attack and damage modifiers you'd normally apply)"
Therefore, it counts as if you're holding it in your space when you use it like a normal weapon. If, as is intended, she activates it, and then pulls out a different weapon, the cool bits of dancing (free MBA) occur.
Second, the power of Greater Dancing Weapon:
For this power dancing occurs in the designated square which is used as the originating square for those attacsk. She therefore provokes opportunity attacks from monsters adjacent to the weapon's square. For monsters adjacent to her, she appears as if she's either concentrating or constipated, and does not provoke for that attack. They get to attack the weapon which will send it back to her hands if the OA is successful.