This is software, it will “contaminate” your application (which is also software) if you include the library as a non-detachable part (e.g. not as a plugin) in the release version of your software. LGPL or GPL v3 with classpath exception won’t.
Rolling back to the beginning. Yes, if you use a share-alike license then it is also viral like the GPL… but as normen says to be clear: is not the GPL. But it will contaminate derivative works.
From the license page:
“If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.”
So, if assets are SA then if you (remix, transform, or build upon) them those derivative works have to be released SA. If code is SA if you (remix, transform, or build upon) the code have to be SA. ie: if you link to it then you are “building upon” it. Just like if you made a warehouse full of CC-SA crates.
An asset pack project can import the worldforge models from a checkout, right-click an asset pack project to select the import option. Though I don’t know what you mean by “more”, theres already all compatible OgreXML models imported.