Hi Alan!
Thanks for reaching out. My name is Erin, and I'm on the Moz Help Team. I'll do my best to address all of your questions!
- I have a list of the top 350 keywords sending volume to my site, sorted by volume. I am using your On-Page Optimization tool to look at the top 10 keywords and the grade for each of the relevant pages on the website. So for "hard wood flooring," I am searching for that term on Google and finding the first listing for my site lumberliquidators.com that comess up. Then I paste that page link into the On-Page Optimizer. Is this the best way to do this to determine performance for the most relevant page? Moz gave this keyword an F (home page) even though LL came up #2 in the organic Google rankings.
On-Page looks at more than where you're ranking for a keyword. This tool is telling you how well optimized your keyword is for the URL your ranking for. You can read more about it all here in this handy article from our Help Hub!
- Who long does it take a campaign to run before all the final data is there? I have ran 3 different campaigns here because I made some changes int he keywords used. Is the last one, "LL SEO 3 - Lorry Terms" complete?
When you initially set up a campaign you'll see GA data (if you have a profile linked), Keyword Rankings (as long as the were added during campaign set up), and your competitive metrics within a few hours. All of your other data should populate within 7 days.
After that, your campaign will update every seven days. So for example, your LL SEO 3 campaign was created on August 21st. That means that your next update will occur on August 28th, and show your data from August 21st-August 27th. Your campaign should also update on the same day every week.
- It says there is a crawl error for Duplicate Content - 42,983 pages on www.lumberliquidators.com have duplicate content - is this possible?
Yes, it's possible. It really just depends on how you have your site set up. Campaigns have a 90% tolerance for duplicate content. This includes all the source code on the page and not just the viewable text. So if a URL is at least 90% similar in code to another URL, this warning will appear.
You can run your own tests using this tool: http://www.webconfs.com/similar-page-checker.php
We don't know what standard Google uses, but it's safe to say they are a bit more sophisticated than us - so you might be okay in this regard as long as you have a couple hundred words of unique text per page. Google won't say how much duplicate content is too much, so we like to be better safe than sorry. 
- I noticed that when I search for www.lumberrliquidators.com on Google it seems to "redirects" to http://www.lumberliquidators.com/ll/home. Could this be impacting numbers in some way?
As long as you have your 301 set up correctly, this should be fine.
I hope this helps! If you have any other questions, feel free to email us at help@moz.com!
Cheers,
Erin