Slashing question and long range attack

Hey,
I suddently got confused about how slashing works.

Let say there is a short range fork and I am an honest block producing staker. I choose a single chain to produce my blocks on, but soon understand I have betted on the losing chain. When exactly can I start producing blocks for the favored chain w.o. gettign slashed? After it has been finalized after 2 epochs (iirc)?

Now let say I a long range attacker. I no longer stake but in the distant past I did. So now I go to the past and create a fork at apoint where I have a considerable amount and stake and can collude with other historical stakers. What happens now? Someone can prove that we are cheating and we get slashed only on the long range fork?