> (1) can one go to 1.8e & then back off to 1.8d? (I.e., is there a problem
> with any new data structures?)

Yes, it should be possible (note that this is not always the case when installing a new version). Some statistics will stop updating while you are at 1.8d or might even be reset, but I can't think of any major problems. I am not making any legally binding guarantees, mind you.

> (2) I've tailored a few  site templates and certainly my list-owners have
> tailored some list templates.  Do any of these *need* to be changed? Have
> any templates been dropped from use?  Anyone know which templates have been
> changed a little or a lot?

I don't think any MAILTPL have to be changed. I can't think of any major changes in this area, except for the MAILTPL that are actually a web page. Some WWWTPL on the other hand have changed dramatically as a result of the new web interface.

> (3) Corollary to (2): How does a list-owner see the new default templates
> (without killing the currently modified templates)?

Personally I'd just GET DEFAULT MAILTPL and use a text editor.

  Eric