Grammar, Usage / Questions regarding parenthetical citations [2]

Hi, everyone! I just joined this community and I'm wondering if anyone can help me with parenthetical citations.

I understand the basic rules, but I have a couple questions.
What do I cite when my information is from an article from a website that does not have an author or a date?
Some article titles are very long; should I put the entire title?
If I restate something I said earlier in the essay that was already properly referenced, should I reference it again?
Thanks!