[Fyron]

Would it be possible to give Asteroid Belts a ship cloaking ability. If a ship enters an Asteroid Belt it in effect disappears and can only be detected by say a Ship/Sat/Recon fighter with scanning equipment.

Yes, it is possible. However, real asteroid belts have vast stretches of empty space between asteroids. So, you wouldn't really be able to hide well in them.

Make it so that the Ship/Sat/Rec.Ftr has to be within one sector of Asteroid to detect anything hiding there.

That is not possible. Tachyon-type scanners are always system-wide.

Also; ships in orbit half the effective range of scanners from other players due to atmospheric/magnetic field interference.

Not possible.

Also can we not have Listening Post's with a range factor e.g.

The scanning ability on facilities is Long Range Scanner - System. It always has unlimited range within a system.

I do not know if the Long Range Scanner ability used on components works on facilities. It probably does. If so, then it would work. However, range 10 covers the entire system unless the planet is on the border of the system. Then, it would miss the opposite border.

PS. How do you make Fighters Jump Gate/Worm Hole capable?

The only way to do that would be to make them Ships. But then, they wouldn't be able to be carried anymore.