This site with the content might be ok, the site with the artificial links will take a hit for link building.

It's not perfect content, it's basically trading someone writing "good enough" content in exchange for a link, so instead of paying cash for a link you are paying indirectly by paying someone to write content for them in exchange for a link.

Google wants to see a site mentioned in the news for instance by an authority site like if CNN did a piece on your niche and linked to your site. That is a natural link. Having a dofollow link at the bottom of a page (many pages on the same site) with your exact desired anchor text after a blog post is nothing more than a paid link, better than article sites like ezinearticles.com who were the first on the chopping block, but now G will come for all the SEOs that have flocked to guest blogging.

Also, G is looking at your G+ authorship to determine how good of a writer you are and where you are posting and if that is tied into your business they will make a determination as to whether you are a low quality writer or not.

I'm just slightly ahead of the curve, if you want to do this just make sure you have the login to the accounts you are guest blogging on always so when the time come that guest blogging is now causing penalties you can go in and quickly remove or nofollow them.

"but a guest blogging campaign should be as much about gaining traffic from referral sites rather than using if purely for link building."

In Google's eyes if it's passing PR it's link building to manipulate rankings, so if you are guest blogging it had better be nofollow and for traffic only, not for SEO because guest blogging is the next form of link building they are targeting because it has gotten so prevalent since Google put the kabash on so many other forms of link building already and SEOs are scrambling to find safe ways to build links that pass PR. Wow that was quite a run on sentence whew.

http://www.example.com/test page.html will be converted to %20 so it could be interpreted as the same page

All three could be considered spaces, I wouldn't use any of them.

http://blogs.iis.net/robert_mcmurray/archive/2011/04/27/bad-characters-to-use-in-web-based-filenames.aspx

Joomla can be SEO friendly, there are custom made CMS platforms, if your site is small you don't even need a CMS.