Does Calvinism state that there are those predestinated to Heaven and Hell regardless of what they could do or believe?
Um, what are you seeking to express?
There are so many jumping off points with that expression that I have to shake my head & say, I don't know what you're asking, but no, that's not a good way to communicate it.
Humanity's nature is such that it will inevitably condemn itself
on the basis of its own works, if God does not unilaterally intervene. So no, not "regardless". There is nothing but the
corrupt human will in the way of people acting or believing -- but there is no
uncorrupt human will. So "could" is ambiguous.
has God already selected the ones He wants to be saved so He has predestinated them to be saved? I was reading the Westminster Confession of Faith and The Larger Catechism and the answer to question no. 17 would make this appear so. Is this right?
Actually -- most of western Christianity
including the Council of Trent (Catholic) and Lutheran thought (Concord) agrees that God has already selected
from the foundation of the world the people He will ultimately save.
But that's nowhere near "in other words" of your initial question.
In Reformed thought people who are condemned are condemned based on their own sinful natures. But people are justified through faith in Christ Jesus, a faith brought about through the regeneration and call of God to those He has chosen.
So, ah, I'm not sure what you're asking.