User-specific new-post.php

I’m working on a site that will have several interns who write only a specific kind of post, and use the same custom fields every time. I’ve found a plug-in (rc-custom-field-gui) that allows me to create a form with a text-entry box for the custom fields each post requires. (It’s sort-of crude, with no error-handling, but it will do.)

What I’m trying to do now, is
(1) eliminate all the unnecessary options from the new-post.php page,
(2) add a blockquote button to the WYSIWYG editor, and
(3) have all of the changes above _only_ show up when one of my interns is using the “new post” page.

I’m sure there must be a way to do this stuff (especially #3), but I haven’t been able to find _anything_ about editing the new-post.php page (or any of the back-end pages, for that matter.) I get the feeling it’s simply a matter of knowing where to look, but I’m still new to WordPress, and don’t even know what search phrase to “google” for!

(I realize this is going to likely involve my changing some files that are part of the wordpress core, which is a no-no, but for now, it may be what I need to do in order to get this project up quickly. Once I learn more, I’ll come back to it & try to do this through the plug-in system.)

If someone could point me in the right direction, I’d sure appreciate it.

Thanks Gang!

Shane