5th dnd – Is a real attack instead of a feint can be used as a distraction for an action of help?

No, it's not a flaw. In turn, PCs attack or help

Your turn

In turn, you can travel a distance up to your speed and Take one
action.
(Basic rules, page 72)

Actions in combat

Attack, Cast a Spell, Dash, Disengage, Dodge, Help, Hide, Ready,
Search, use an object (Basic rules, pp. 74 and 75)

Choose one, unless a game function gives you one more.

Your example

P1 and P2 face a monster M1, with the order of initiative of P1, P2,
M1. P1 declares that he wants to use his "Action Aid" but wants
use an attack as a distraction. P1 attacks and succeeds. P2 does
his attack with advantage.

P2 does not attack with advantage. P1 used his action in combat to attack, not to help.

If the PC takes the attack action, the help action is only an option of this turn if a reaction class / bonus function / spell allows the help action to be applied. as a reaction or bonus action.

  • The thief (Mastermind) has a feature that offers an allied advantage.
    The Battle Master Fighter has a similar maneuver that provides
    advantage over the attack of an ally.

The action of attack is a complete turn spent trying to succeed an attack. It's not just a sword, it's six seconds of banging action to try to hit. The d20 roll determines whether the combined efforts succeed or fail.

The fake is just that: a distraction that is never meant to be a hit, but rather to make it more likely that an ally is dealt a blow.

Pack Tactics – a game feature that does it

I think it's worth mentioning that there is a game feature that gives the effect of not trying to use Help to do this. If the PC plays as a kobold PC (ref: Volo Guide on Monsters), and P1 and P2, and they are within 5% of M in your example, they give each other an advantage in their melee attacks against Mr. Wolves and Kobolds {Monsters / NPCs} (Rules basic, pages 159, 123 and 142 respectively).

Pack Tactics. The kobold has the advantage on a jet of attack against a
creature if at least one of the kobold's allies is within 5 feet of
the creature and the ally are not incapable.

dnd 5th – Can an invisible servant create a distraction that gives you an edge advantage?

This spell creates an Invisible, Stupid, Shapeless Medium Force that performs simple tasks at your command until the end of the spell.

The spell does not say that it's about one creature or another being able to take action. Things do what they say they do. Note that the Find Familiar spell indicates that the thing invoked can take action.

Your familiar acts act independently of you, but he always obeys your orders. In combat, he launches his own initiative and acts in turn. A pet can not attack, but it can take other actions as usual.

However, the familiar is able to do simple tasks as a human servant:

Once on each of your tricks as a bonus action, you can mentally command the servant to move more than 15 feet and interact with an object. The servant can perform simple tasks like a human servant, such as fetching things, cleaning, mending, folding clothes, lighting fires, serving food and pouring wine. Once you have given the command, the server runs the job to the best of its ability until it finishes, and then waits for your next command.

I would say that dropping dishes is something the servants do, and that it is essentially instantaneous (no hesitation, because the servant is without spirit). This should be able to occur during the bonus action on the player's turn unless otherwise (ie the activity takes too much time).

Result

Causing a distraction by dropping plates is certainly something that the servant should be able to do during the player's bonus action. However, as a DM, you decide what will happen next. When I'm DM, I personally use the rule of freshness – in this case, I'd probably grant a saveship of wisdom or intelligence control of the creature (to an appropriate distribution center ) on the first set of plates, then I would ignore future sets or with advantage. If the player starts to run with stacks of dishes otherwise, remind them that the dishes cost gold and that people do not like their dishes to be stolen.