While other sub systems are at play in CT, the core mechanic is roll 2D6 against a target, with modifiers, trying to equal or exceed the target number.
Keep in mind, CT did not have an integrated task system. There are lots of extras added here and there in adventures often only relevant to the adventure.
JUST using FF&S as a tech builder, while putting aside all the Traveller technology isn't Traveller. You could use FF&S to build Car Wars vehicles. Not really Traveller. You could use FF&S to build Star Wars ships. Not really Traveller. You could use FF&S to build Vietnam War era equipment for a historical game. Not really Traveller.
However, if you're still substantially using the Traveller tech suite (maybe a different FTL, or maybe dropping anti-grav), sure.
Keep in mind, CT did not have an integrated task system. There are lots of extras added here and there in adventures often only relevant to the adventure.
No, I would say not. The rules you're using there are GDW house system; you could as well have used Twilight 2000 as the basis.So will you answer mu final question, if I use TNE rules and FF&S to make a bespoke setting am I playing Traveller?
2d6 system? Nope
Third Imperium Setting? Nope
Using a set of Traveller rules as they are intended to be used? Yup.
JUST using FF&S as a tech builder, while putting aside all the Traveller technology isn't Traveller. You could use FF&S to build Car Wars vehicles. Not really Traveller. You could use FF&S to build Star Wars ships. Not really Traveller. You could use FF&S to build Vietnam War era equipment for a historical game. Not really Traveller.
However, if you're still substantially using the Traveller tech suite (maybe a different FTL, or maybe dropping anti-grav), sure.