Hello if e.g. my Rancor is focused and i play Wild Attack before i play Feral Swipes :

1. Do i get to do 5 Red die attacks

2. The first of these Attacks will be Red Red Green (from Focus and Wild Attack) ?

1.No.
2.If you are focused and play Wild Attack on the first one.

Focused doesn't modify your attack pool, it adds a green die when you declare an attack.

Feral Swipes is a special action. If you want to use both, you spend an action to perform Feral Swipes first, which determines the number of attacks to perform. Then you perform the specified number of attacks, and you can play Wild Attack on any of the attacks you perform (the first step of an attack is declare target, which is the same as declaring an attack). Adding dice to the attack pool doesn't retroactively change the number of times you can perform attacks from Feral Swipes.

"attack pool" when stated on effects like this is considered to be the starting (printed) amount. That's the easiest way to explain it.

So most common figures have 2 die in their attack pool and most titular characters (or massives) have 3.