Basic question on keywords in domain names and 301 redirecting

I'm new to SEO and I know this is a very common scenario but I can't seem to find any definitive info. Lots of discussion and opinions on the subject but often conflicting and nothing really official. I've had site "X.com" up for almost a year now. The name "X" itself has no keywords in it so I'd like to create a domain name that does have keywords. "X.com" should ideally be maintained as the primary site however. I'd therefore like to create a site with some relevant keywords, call it "Y.com", and redirect it to "X.com". My basic (sometimes overlapping) questions are therefore:

1. Should I simply create a single page on "Y.com" that does nothing but redirect to "X.com" (via 301)?
2. Without adding any content or (explicit) backlinks to "Y.com", will searches for "Y" eventually push "Y.com" up the rankings (and hence generate more traffic for "X.com")?
3. Should I add some (unique) content to "Y.com" and/or backlinks but automatically redirect to "X.com" anyway?
4. Will Google penalize me for any of the above? (since "Y.com" is redirecting for SEO reasons only)
5. Would it really be better to turn "Y.com" into a real site, with unique content and no redirection? It's a maintenance issue of course (maintaining multiple sites), but if the above scenarios won't help, then it's an option worth considering.

Perhaps this thread can clear up the issue once and for all (for me and many others no doubt). Experienced opinions are preferred though. Thanks very much.

if you want to promote your site Y.com, use 301 redirection X.com to Y.com. If you use 301 redirection Google will redirect all back links, Index status, Link Juice, Page ranks which all are belongs to X.com. If you want to promote both X.com & Y.com, you need to create unique content, meta tags, niche back links & etc.

myseopandit wrote:

if you want to promote your site Y.com, use 301 redirection X.com to Y.com. If you use 301 redirection Google will redirect all back links, Index status, Link Juice, Page ranks which all are belongs to X.com. If you want to promote both X.com & Y.com, you need to create unique content, meta tags, niche back links & etc.

Thanks your suggestions