After making/importing a new list on Skritter, do you recommend that I click "all words" and then click "add to queue" , or should I not do that and just study the list by clicking on "cram list" and then study the list individually, and also study the "everything" queue once a day to bring the number of items due down to Zero ?

So basically, my question is, should I bother "choosing all words" in the lists and then clicking on "add to queue", or is that not necessary?

Don't do that. We'll be redesigning it so that it's not tempting to do that. If you do that, the words will be tagged as coming from your queue instead of that list.