In vega i would get a tank or storm
In antares, a storm because most of the missions you'll need to kill some stuff
In gemini, possibly the hardest system, you'll need an engineer, because most of the gemini missions require escorting ships to places.
In Mizar, while on baumar, you'll need speed for some missions, and some you'll need defense, so either shock or storm, when you ge to molikar, get a tank, you'll need quite alot of defense whe doing those molikar missions.
In Sol, on Mars, you'll need firepower and sometimes, defense, so Rank 45 storm or tank, on the moon, you will need defense because moon mantis for rank 45 ships cause quite some damage, so a rank 45 tank. When you get to Earth, You will definitely need a Rank 60 ship to complete those Earth missions, so either a tank or storm.
Correct me if i'm wrong.