I'm currently asking questions that don't seem to have a tag-wiki entry for the tags I need to use, and there's perfectly good tags on SU for those pieces of software. Can I copy the tag wiki information from SU (and how would I attribute?) to help initially populate these tags?
All content on SE is CC :)
I wrote a lot of the tag wikis on Android Enthusiasts, so I have no problem copying my own content. But even copying from other users' tag wiki edits shouldn't pose a problem in terms of "being stolen/borrowed".
However, there are things to consider when doing so: a 1:1 copy only fits in rare cases. In most cases, adjustments are needed to reflect the tag's purpose on the specific site. The very same tag might serve a completely different purpose on another site. To give a somehow "heavy" example: On A.SE we deal with "Android issues from the users' point of view", and development questions are strictly off-topic. So you shouldn't make a 1:1 copy of our
development tags :)