SEO... Few Questions

While I consider myself somewhat familiar with the basic structure of on-page SEO, I recently purchased some niche blogs pre-loaded with articles.

Naturally, I intend to do keyword research, and write new content. For now, I simply imported the articles that were included just to establish the base foundation for my niche blogs.

What I am curious to know;

1.) -Will these articles cause long-term damage being they are 'not original' and most likely can be found elsewhere on the internet?

2.) -Syndicated content: If I wanted to just fill empty spaces (for now) and pulled articles from EzineArticles per say to produce temporary relevant content (*until I can write my own, and I WILL keep the resource box in tact), will this be viewed any different than loading the prewritten articles that were included with my blog purchases?

-Is one more beneficial than the other?

Obviously, I intend to devote a great deal of time writing unique content and replacing the widely distributed articles on my sites... once my new sites are set up.

But I do not want to load these sites, and publish the content; if I am damaging my initial indexing with "G" and if it'll cause long-term effects in my getting some credibility in the SERRP's.

Further more, it obviously takes time to transfer DNS, install WP on each domain, upload the themes, tweak and update the plugins, add widget, rss, social links, add Amazon store, CB ads, etc...

I am currently in the process of doing this with 10 new niche sites.

So my thought was just get em up, get my Amazon stores working, and all affiliate offers set-up first... then worry about replacing the content. :confused:

I began uploading and publishing these sites yesterday...

Today I noticed (through installed tracking) that I am already getting indexed for the content within 24 hours of publishing these sites, which I think is Purdy damn quick. *Also, I am running my sites through TrafficTravis to optimize everything I can, and adding <h1> tags, meta data, etc... to get as much leverage as possible.

-Is this the best way to do this???

or

-Should I NOT publish them until my unique content is written?

For the record, my main goal is to draw targeted traffic through my own articles content, syndication, and possible do a few PPC campaigns, therefore, I am NOT all that worried about pleasing 'G' - I just don't want these sites to be penalized right out of the gate either.

Open to any suggestions, Thanks

-Art