Guys I think I finally found the solution to this problem due to some good karma. This morning I was helping somebody on SCN with a temporal join and created an analytic view using tables in my personal schema. To my surprise the view failed to 'activate' with 'unauthorized' error. Since I was using tables in my personal schema i looked at privileges for _SYS_REPO and it indeed already has SELECT privileges against my schema. So I started looking at _SYS_REPO's privileges against other schemas and noticed another schema (that works) had select but with also 'grantable to others'. On a whim I added 'grantable to others' on select against my schema for _SYS_REPO and retried my procedure and it worked!
Now I'm curious if anybody knows why _SYS_REPO needs 'grantable to others' and also I'm assuming this means all temp tables are created in the invokers personal schema?? Albeit temporarily.
Thanks all!
-Patrick