Mix aggregator with flexynode and taxonomy

Hi!

I'm very new to Drupal. I'd read some info about it and decided to build a portal on it.

Now I need to create a centralized newsline. For that I gather content (news, articles, etc...) from several sites.
I'm playing with Rss Aggregator and found it stores gathered content into it's own format.
Is it possible to hybridize aggregator with flexinode or at least with usual story? So that this module would produce objects of standard type with standard behavior. I want to control content with workflow - moderational policy, to see feed content in my newsline, also I want my users could write comments to this content.

The next. Can I transmit taxonomy information via rss feed? So if author of some site marked an article with terms "A" and "B", how can I get this information?
As far as I know, RSS 2.0 allows to transmit category info with special tags like this:
1765
Does Drupal rss aggregator support this feature? What about multiple categories? Of course, all sites in this ring must have the same taxonomy. Is it possible to share taxonomy with several drupal instances places on different hosts? May be there's some standard way to publish taxonomy on the net?
I googled a little and found XML Topic Maps and Web Ontology Language. Do you know what status do they have? What about their support in Drupal and other tools?

Thank you very much in advance.
Eugene