**1. I'd like to remove most of the blog articles as I want the new site to be very high quality, but isn't it dangerous to do a 301 redirect to the same page for all these articles? **
Correct - you don't want to be redirecting multiple pages to a single page. This is bad for user experience and SEO.
**2. I want to focus on the new site as the current site has too many issues but still managing to hang in their. is highly outdated yet I don't want to spend a ton of time on the site before the 301 redirect. With the Pigeon and Panda 4.0 rumors being released soon, I want to get the new site completed ASAP. Do you think it's better if I fix the **
If moving the site, don't forget to advise Google in Webmaster Tools, as well as 301 pages. In terms of fixing issues, I would be tempted to correct issues before moving over so you don't have problems follow you.
3. Would removing cloudflare make things better or worse with the crashing of my site due to high traffic (mainly spam on the blog.)
I can't really give a definitive answer on this one, but I know of a lot of other cloudflare users who have experienced problems like this. I would also be looking to use Akismet to control the spam that comes through the blog comments.
4. My best article by far is outdated, but should I waste time updating it before redirecting or should I just get the new site going?
As long as it gets updated, I wouldn't worry about it beforehand. Lots of old articles can be resurrected by re-working them again to make them more current.
**5. Anything I can do to slow down these spammers on Wordpress? I noticed most of them are checking for vulnerabilities but I'm keeping it up to date, have caching setup. **
See the answer to question 3 above.
I hope this helps a little.
-Andy