As described in @Szega's answer (emphasis mine):

you can aid a friendly creature in attacking [ a creature within 5 feet of you ]

To help in attacking (doing a feint), you have to be within 5 feet of the enemy, not 5 feet of your ally.

Timing-wise, the familiar goes into range of 5 ft to the target, uses the Help action to distract, and then moves out of range.

The owl indeed seems to be the best familiar to do this, because of its Flyby skill:

Flyby. The owl doesn't provoke opportunity attacks when it flies out of an enemy's reach.

But in general, familiars are not good in combat due to their low AC and low HP.

As described in @Szega's answer (emphasis mine):

you can aid a friendly creature in attacking [ a creature within 5 feet of you ]

To help in attacking (doing a feint), you have to be within 5 feet of the enemy, not 5 feet of your ally.

Timing-wise, the familiar goes into range of 5 ft to the target, uses the Help action to distract, and then moves out of range.

The owl indeed seems to be the best familiar to do this, because of its Flyby trait:

Flyby. The owl doesn't provoke opportunity attacks when it flies out of an enemy's reach.

But in general, familiars are not good in combat due to their low AC and low HP.

As described in @Szega's answer: (emphasis mine)

you can aid a friendly creature in attacking [ a creature within 5 feet of you ]

To help in attacking (doing a feint), you have to be within 5 feet of the enemy, not 5 feet of your ally.

Timing wise the familiar goes into range of 5 ft to the target, uses the help action to distract and then moves out of range.

The owl indeed seems to be the best familiar to do this, because of his Flyby skill:

Flyby. The owl doesn't provoke opportunity attacks when it flies out of an enemy's reach.

But in general, familiars are not good in combat due to their low AC and low HP.

As described in @Szega's answer (emphasis mine):

you can aid a friendly creature in attacking [ a creature within 5 feet of you ]

To help in attacking (doing a feint), you have to be within 5 feet of the enemy, not 5 feet of your ally.

Timing-wise, the familiar goes into range of 5 ft to the target, uses the Help action to distract, and then moves out of range.

The owl indeed seems to be the best familiar to do this, because of its Flyby skill:

Flyby. The owl doesn't provoke opportunity attacks when it flies out of an enemy's reach.

But in general, familiars are not good in combat due to their low AC and low HP.