Welcome Zeph3r
In answer to your question, your characters have been wiped out because of in activity, if you have a char that you haven't logged in 6 months, it gets deleted automatically by the server.
And to the second question, There have been Tech restrictions made to avoid people getting whatever they want of ships and equipment, you can check here and here.
Hope that my answers are satisfying enough, however if you require more details or answers to specific questions, I'm all ears so does the community, Thanks and have fun .
If I am flying The Council ID, I cannot use Bretonia Civilian Weapons | Bretonia Civilian Ships (Light) | Bretonia Civilian Ships (Heavy). But I can use Bretonia Lawful Weapons | Bretonia Lawful Ships at 90%? And I can use Zoners Weapons | Zoners Ships at 75%?
What does this mean?
I am currently flying a Mammoth with a Freelancer ID. When I undock I get a message about power core at 90%. This is because my ID is only 90% compatible? What would happen if I installed something or bought a ship that was not compatible?
Yes, that is probably because the Mammoth is a lawful transport, not civilian, it should work fine with Navy/LPI/USI/IC/DSE IDs because they are Liberty lawful, but you can fly it with Freelancer ID, However 90% isn't a big deal, you'll probably not feel it, what you should be afraid of is -75%, those could drain your power core a lot, just remember keep the tech char in your mind always, for the sake of RP and fun, Cheers!