Hi Richard,
Thanks again for your help on this and continued interest.
Sorry for the delayed reply, when one is working on websites...time just flies right by in an amazing way.
I can confirm without any real doubt that the icon font problem is NOT WP-Super Cache.
IF that was the key source of your interest in the entire issue, you may wish to stop reading. If however, your interest was more generalized as a WP guru, by all means read on!
Since I had to do some maintenance and other work on a few other sites, none of which have ever had WP Super Cache installed, and now seen the same behavior of the icon font when I attempted to implement it on one for the first time, I've moved to drilling down a list of possible causes.
While I may be giving the icon font another go on the site which prompted my posting - grassrootsne.com - before you read this reply, it's possible for you to see the identical problem here:
(IF, however, you see three icons below the nav bar when you land...well...that means I've figured this out! In which case, I'll be back to update in the hopes of helping some other frustrated person.)
I've successfully implemented the icon font on another set of sites recently:
dbandrmarketing.com
store.
music.
famag.
As I noted originally, the grassrootsne.com site and others, including dbandrmarketing.com, et al, have very many similarities...
Theme / child theme frameworks
Same wp_enqueue function (changed the file paths, as appropriate)
Same CSS
Same location of font files
Many similar plugins (but not all)
The tarahdawdyphoto.com has all of these similarities, too. Neither dbandrmarketing.com nor tarahdawdyphoto.com have had WP Super Cache installed, however. One works, one doesn't.
I've eliminated the htaccess files as suspect; the sites just mentioned have identical htaccess file contents. I realized this had to be considered, since grassrootsne.com has slightly different code, which is an updated version (based mostly on HTML5 Boilerplate).
So...by processes of elimination, I'm down to potential differences in...
1) Plugins
2) Font files generated by Icomoon app
Finally, I also must examine...
Potential differences in versions of the theme / child theme frameworks...there WERE recent updates.
If I don't find a solution this way...I'll start over again and see what I might be missing.
Once again, thanks for your help and information. I'm so glad I inquired originally, because, as I said, WP Super Cache really did speed up the site tremendously even though it had a number of problems. Some of 'fear of the unknown' regarding the plugin's impact on future changes / resolving problems have been allayed entirely AND I'm now seeing, live, how turning it off as you instructed allows me to work. I'll be installing this on other sites when they are complete to optimize their performance as well.
Shelli