Are there any chances that we see a Nimbus class V-Wing? or other ships ?

The synth reactor I believe has a cargo access port either outside or through the cockpit.

Is there a way to add synthetic fuel to the reactor?

Ive no clue why I couldnt fire them then, thats quite weird

They're energy-based, they don't use Conveyors.
Weapon-Core Scripting

I just couldnt actually fire them; i couldnt find connecting conveyors for the turrets either

Are these meant only for creative?

I tested them all, the night I released it.
Ions & Laser-Cannons are turrets, and on the right-side cockpit have on\off button, while the left cockpit had control tabs for each turret.

Proton-Torpedoes, were on both bars.

Thats fair, i also noticed that i wasnt actually capable of firing the weapons, besides the proton bombs

Yes.
As it's 37+ Block Descriptions
I will Replace them, I wanted the Ships functional however

Both this and the other fighter you had just published have TIE block descriptions-