We fixed some of the issues on our Skype session last night.
Part of the problem is the ACL's on the elements you are using, so it depends who is submitting the form as to whether the element data is present. The ACL's are applied to the email plugin, so if the user can't see the data in the form, it can't be included in the email.
However, there are also some other issues which are just problems with the way data is passed around in 3.0. Changing to using _raw for one of youplaceholders fixed on issue, and using {rowid} instead of the ___id element fixed another. Those issues have been resolved in 3.1, where we have greatly improved the way we represent submitted data internally, when plugins need to see it.
We still seem to need to do some more work to get it just right, but I fell asleep around 5am, in the middle of trying to fix the first of the two email plugins, after we got the second one (more or less) working.
-- hugh