## Time doesn't exist within turns
In D&D 5e, movement and actions do not consume time. The game is inherently turn based. Actions happen in sequence each happening completely before the next can begin. The one exception is Readied Actions, which may interrupt other actions during a turn. 

In the case of Readied Actions, once the trigger occurs the action happens as soon as the triggering action is completed. Then the readied action takes place, completely, before resuming normal initiative order.

When you trigger then Owls movement, it completes the movement entirely. Then you return to whatever was next in normal initiative order. 

### Case 1
 The sequence of events for initiative order Owl -> Kobold -> Target is as follows (note; I have left out bonus actions, which can be taken at any point in the turn):

 1. On the Owl's turn:
    1. Owl uses it's movement to fly up to the target.
    1. Owl uses it's action to Ready movement to move to a set position when Kobold signals it.
    1. Owl's turn ends.
 1. On the Kobold's turn:
    1. Kobold uses it's action to Attack. Getting as many attacks as it can take with the Attack action.
    1. Kobold uses a free activity on their turn to signal the Owl.
    1. Owl's readied action triggers. Owl moves to position.
    1. Kobold's turn ends.
 1. Target's turn

### Case 2
The sequence of events for initiative order Owl -> Target -> Kobold is as follows:

1. On the Owl's turn:
    1. Owl uses it's movement to fly to a safe place.
    1. Owl uses it's action to Ready movement to move next to the target when Kobold signals it.
    1. Owl's turn ends.
 1. Target's turn
 1. On the Kobold's turn:
    1. Kobold uses a free activity on their turn to signal the Owl.
    1. Owl's readied action triggers. Owl moves to position.
    1. Kobold uses it's action to Attack. Getting as many attacks as it can take with the Attack action.
    1. Kobold's turn ends.

In both cases the Kobold can get it's full turn of actions/attacks with benefit of Pact Tactics. This is the combat system working as intended.

### A Caveat
It is worth pointing out that this will be more difficult to pull off with more than one target as the initiative order won't also suit you. Also targets could Ready an Action to attack the Owl when it comes within range, which would trigger before the Kobolds attacks, potentially negating Pack Tactics.

## D&D isn't a realistic combat system
The combat system in D&D does not attempt to replicate a realistic combat environment. Ideas such as movement taking time or actions occurring simultaneously are not compatible with the game. 

While your attempts to make this *logical* and account for realistic movement are admirable. They do not align with the actual rules of combat and action resolution.

Were I to DM this situation I would allow it exactly as the rules intend. You however, are free to house-rule any modification you wish. Simply discuss it with your DM as it is their ruling that will matter at the table.